When I first heard about the garden bridge, I thought it was a nice idea. A big pedestrian bridge with a park on it, joining up attractive areas of central London. What’s not to like? It sounds a little bit magic: a garden on a bridge. Wow, there’s a whole tree growing on that bridge! Like an aquarium in a pillar, a hotel made of ice, or a firework on a hat.

It’s got a dash of hanging gardens of Babylon, a touch of rooftop pool, and a smidgen of the old London Bridge, which had shops on it and one imagines as very picturesque, though probably didn’t look so to people at the time who didn’t have any ugly concrete or uPVC to compare it to and were fed up with everything being so damp and smelly. Not to mention the high infant mortality rate. And complete lack of democratic accountability. In fact, the more I think about it, the more I realise history must have been really difficult to enjoy if you were actually in it.

That’s what many of us are finding at the moment – so it’s comforting to reflect that any current issues will, in time, be no more troubling to people than the heads on spikes at medieval London Bridge are to us today. Trump, Isis, Putin, Syria, Brexit, the death of Prince – it all just adds to the ghoulish heritage detail that’ll enliven our history-buff descendants’ away-breaks in the boutique hotels of the future, complete with genuine early-21st-century double glazing and patchy wifi, and a building “which is, in places, still physically attached to the planet’s surface”.

It doesn’t feel like the right time for a blowout. Maybe a decade ago, when London was optimistic and self-confident

So it would be sacrilege to demolish the garden bridge. Leave it where it is, I say! OK, it’s a bit tatty now – most of the shrubs have withered and recent analysis of the soil found it to be 72% pigeon excrement, but it turns out bindweed absolutely thrives on the stuff, which provides lots of sheltered hiding places for junkies.

I do realise it hasn’t been built yet. I’m just trying to work out what I think about it and the conclusion that I wouldn’t demolish it is a start. But, on reflection, I don’t think it means I’m in favour of building it. It may mean I’m just in favour of doing nothing in general. Maybe I’m a radical ultra-status quo-ist: “We believe in leaving things as they are, regardless of how that is. Don’t build anything, don’t knock anything down. Don’t pass any laws, don’t repeal any laws. Don’t start a genocide, don’t stop a genocide. Just leave well alone, you’ll only make things worse, be it utopia or hell on Earth. We’re already worried about the unforeseen consequences of saying this.”

But I don’t think it’s that. I’ll never be totally convinced of the futility of human endeavour while there’s a functioning toaster in the world. I think I’ve gone cold on the garden bridge because I’ve been made too aware of what building it would involve. The initial implied casual question, “Do you fancy a garden bridge?”, to which my instinctive response was “Yeah, OK,” has been complicated by hearing too much about how it’s to be achieved. It’s like I’ve accepted someone’s offer of a biscuit and now, after eight minutes of them clanking around in the kitchen, they’re proposing to pop out to the shop.

Last week came news that the bridge’s estimated cost, which last year was revised upwards to £185m, may rise again and that the Garden Bridge Trust is facing the possibility of “further delay to the project” and wondering “whether the project remains viable”. Apart from public grants, the trust only raised £13m over the last 17 months, has yet to secure landing sites on either river bank, has no commitment from the mayor of London to cover the bridge’s projected £3m annual running costs, and is £56m short of having enough money to build it even if the budget doesn’t go up which it probably will (see above).

“Oh, don’t bother then!” I want to say. “We don’t need it. We didn’t want to put you to so much trouble.” The budgetary struggle sits ill with the enterprise’s frivolous aim. They’re not building a hospital or a railway, it’s not a cure for cancer or a voyage of discovery, it’s a snazzy park, a neat trick: trees on a bridge. But like every magic trick, if you show the audience the massive hassle involved in creating the illusion, they lose their sense of wonder and think it’s not worth it. It’s too much for the prospect of a silly, jolly thing – this is why restaurants don’t charge till after pudding.

Illustration by David Foldvari.

It doesn’t feel like the right time for a blowout. Maybe a decade or so ago, when London was optimistic and self-confident. Today the city feels divided and hated. It’s racked with the evidence of increasing global wealth inequality – unaffordable property prices, iceberg houses, punishing rents, mansions left empty by foreign investors, millions enduring long, chaotic commutes on decrepit Victorian railway lines – just as its main industry, the financial services sector, propels that inequality. Meanwhile it’s viewed increasingly dimly by the rest of the country as out of touch with national reality and a sponge for government attention and investment. It’s a provocative moment to piss away £200m on a window box you can walk on.

Public libraries are closing. That’s the clincher for me. For others it might be the parlous state of the NHS, student tuition fees, or the ease of getting across the Thames with the currently available crossings. For me, it’s libraries. Probably because, like the bridge, they’re something some people argue are unnecessary: they say they’re used less, and that the internet renders them obsolete as a way of freely accessing knowledge.

There’s some truth to this (though the internet doesn’t render them obsolete as nice, free places to sit). But the pillars of civilisation don’t currently feel so secure that, when libraries start closing, we can assume it’s happening for sensible reasons rather than because our society is in terminal decline, because the people who need such places are poor and so don’t matter.

Libraries symbolise a commitment to learning, community and equality that can no longer be taken for granted. At this dark, divided time, we need those symbols to stand, not be converted into flats. The price of a magic tree bridge could keep hundreds of them open for years. That realisation would spoil my enjoyment of a new, slightly leafier view of London’s river and its gleaming banks.