Bobbie Johnson, co-founder of new science and technology publisher MATTER

These are tricky times for Apple's legion of fans and supporters. The iPhone and iPad have helped the company underscore its position as one of the biggest, most powerful businesses in the world, but the whispering campaign is out there. Can it really survive without Steve Jobs? Where's the vision now?

You can see fear starting to peep through in all sorts of ways. Strategically, Apple now seems to be focused on small changes to big products, and that has its followers rightly worried. After all, a smaller iPad might be popular, but it is not world-changing. Rumours abound of a cut-price plastic iPhone aimed at the Chinese market: a canny business, if it works, but not in keeping with the company's traditionally high-end approach. Some of the faithful are shaken.

The result? The stock price is down nearly 40% from last summer, and some shareholders are revolting. Reading too much into the wisdom of flighty investors is foolish, of course. But the rumblings reflect some real concerns about Apple's long-term prospects. Staying on top for ever is hard, and there's a definite feeling that its time in the sun might just be coming to an end.

Mike Butcher, editor of TechCrunch Europe

Surely you have not lost faith that Apple's secret weapon – Sir "Jony" Ive, our very own James Bond of design – can't come up with a few more gadgets that even Q would be proud of? Keep the faith, Bobbie!

But I digress. To answer some of your points: whispering campaign? Ah yes, this would be the usual trotted-out argument that because we haven't yet seen an Apple-branded hoverboard appear the company must be out of ideas.

That would be to misunderstand Apple's entire product strategy. Apple doesn't really need to invent anything, merely to take an idea and make the very best product associated with it. Apple didn't invent the PC, yet made the Macintosh, the computer that even many PC users grudgingly preferred. It didn't invent the smartphone, yet it took the idea and created a revolutionary touch device that eventually cowed the once mighty Nokia. If all the reports are correct it will do the same to television, and, it's rumoured, to the next wave of wearable devices such as the Fitbit and Nike+ Fuelband, with its own iWatch.

Whenever Apple launches a product, it goes for broke, then rolls out subsequent iterations until that product is almost perfect, and usually the best in that market category, almost to the point where we are fooled into thinking Apple invented the thing. Granted it's going to be hard to improve on the lightweight iPhone 5 other than with a better camera and flash, but you can be sure that deep in Apple's labs they will be thinking about the eco-system of products – perhaps even home automation and devices for cars – to build around it.

As for China – Google is, by its own choice, locked out, and the Chinese are so hot for the iPhone they are even making clones of them. A cheaper iPhone won't damage the brand in these emerging markets, but simply provide a revenue home run for Apple's bank balance. It couldn't care less about its stock price.

BJ: It's all a question of context. Apple's problem is more about its failure to live up to the insane expectations of the public than its bottom line. But that image is its trump card, and if it's lost, can it be regained? I'm not saying the company will collapse and disappear. But will it manage to drive the next wave, and the next wave, and the next wave?

The warning signs are already there. Take a product such as Glass, the head-mounted computer that Google says will change our lives. You can see Apple already seems a step behind. Yes, Glass and all its cyborgian, privacy-invading connotations is terrifying — but in many ways, it's precisely the sort of product (and chutzpah) that you might expect from Apple. Instead, what secret project is the sainted Jony Ive said to be working on? A watch.

It's not cynicism to wonder where the leadership at the top will take it. It's realism. Tim Cook, the man who took over when Steve Jobs died, is an excellent manager, but he lacks the force and, frankly, the arrogance that made his predecessor so successful. Cook has spent his time in charge dealing with internal politics – firing his rivals or making bad hiring decisions – and facing up to external threats such as Samsung and Google, which are desperate to kill it off. Jobs was prepared to do anything to win, and he ran the place with the hand of a dictator: it's hard to imagine Cook shutting down an entire profitable product line because he wants to step on his rivals with that Next Big Thing.

PS – did you not see Skyfall? Q's gadgets ain't what they used to be.

MB Thinking that Apple must follow Google, and Google must follow Apple (as it clearly did with the Android smartphone operating system) is perhaps a misreading of where the companies see themselves in the future.

Google's business model is to organise the world's information so that it can sell ads against all that content. Perhaps even to ultimately predict what we want before we know we want it. Android is merely a Trojan horse for this business model, to harvest gargantuan amounts of information about the world and maintain its lead as the world's biggest ad platform. Apple's, by contrast, is to marry software services (such as iTunes music and apps) and hardware in such perfect synchronicity that we simply must buy the devices themselves.

Yes, Steve Jobs is not there, but do we not think that in the months prior to his death he did not pass on his vision for the company and the future of technology? There's no doubt that, like the frozen head in Dennis Potter's Cold Lazarus play, Steve Jobs's vision lives on. His DNA runs through Apple perhaps more than any other company in the world before or since.

PS – pah! In Skyfall Q has clearly been taking tips from Jony – keep the user interface of the gun as simple as possible!

BB: All great companies have their time. General Motors was the pride of 1920s America, but by 2009 faced the ignominy of bankruptcy. IBM, the biggest company in the world in the 1950s, is a very different beast today. Further back, even giants such as the Dutch East India company, which changed the world profoundly, burnt out in the end.

We don't know what the next rabbit Apple could pull out of the hat might be, and clearly it's using its corporate dominance to reinforce itself and lock out its rivals. But the questions it faces today – and the world it finds itself in – are new to it. It's enjoyed a great ride, and it may continue for a long time yet. However, if there's one thing it should have learned from Steve Jobs, it's that nobody can last forever.

MB: I think we have a better sense of where technology is going, compared to the days when IBM still made calculators. We know now, for instance, that a world populated by an "internet of things" will be a reality in the next five to 10 years. We know that computing power may one day reside on the bands of a string of DNA. Apple will know this, and its raison d'être is to bring products to market that realise that future in a tangible way.

Sure, not all companies survive. But few companies are as rich as Apple, or have so much market dominance or such an enduringly enthused fan base. Tim Cook may not be Steve Jobs but the ousting of the head of its Maps after that particular debacle shows Cook has the will to keep Apple on course. Combined with Ive, Apple has the talent it needs.