A recent post of mine on reddit.com/r/btc detailed the Bitcoin (Cash) network's potential to, by the time the block subsidy ran out, sustain transaction volume that would provide miners with the same incentive to mine as they have now (including the block subsidy) with only 0.1 cent fees. (The post can be found here for context: https://www.reddit.com/r/btc/comments/7gy9jt/to_any_concern_troll_worried_that_the_bitcoin/ )

Ironically, I wrote that post as a response to concern trolling and, in that very post, I was presented with another set of "concerns" by someone whom you may or may not consider a "troll".

Their first goal was to argue that my post was:

"...based on the premise that EVERYTHING occurs on chain which implies that there will NEVER be a side chain solution or a lightningesque solution because if there was a significant amount of on chain activity that left then it would mean that there wasn't enough fees for the miners anymore and the network would fail. Unless you then made the blocks smaller to create a fee market."

This point was easy enough to refute. My post wasn't based on the premise that EVERYTHING occurs on-chain because literally any non-zero percentage of transactions could be taking place on-chain and, as long as that percentage of transactions represented the number I specified in my post of 208,333 transactions per second (or tps), then 0.1 cent transactions would provide the miners with the same block reward they receive on the btc chain today, with no block subsidy.

But maybe you can already see the "concern" here, and the potential for it to derail any productive forward thinking.

He also made a quick point that was:

Even if everything was working perfectly with no block reward the fact that a single off chain innovation could potentially destroy the delicate balance of the set-up you've outlined indicates it is not suitable for the long term.

The only new claim here is that the set-up I outlined requires a "delicate balance." But I was only showing that it would be possible to sustain the miners with some X number of transactions per second with some Y fee per transaction, and that the blocksize required was not unlikely to be viable (if not peanuts) by the time the block subsidy ran out. What is there to be delicate about it?

I imagine that the balance they're referring to here is simply the situation where, given the choice between on-chain and off chain, people might choose off chain and leave the miners with less incentive. Whether this is a "delicate balance", however, is debatable.

Miners have secured the network for much much less than they are currently earning. In order to argue that the balance is delicate, one would need to show empirically that, at some specific lower incentive, the network becomes nonviable. It seems more likely that it would only reach varying degrees of lower security as the mining reward goes down.

On top of that, the potential for the mining incentive to suffer in that way is based on the assumption that there will be prevalent use cases for off chain transactions, given a non-congested chain. At least as far as the lightning network goes, I would argue that, from what I've seen of the technology and its limitations, that it's not a threat to the number of on-chain transactions.

Because of the nature of payment channels (and funds having to be tied up in them), it's not unlikely that it will only ever be viable for "regular" use by large financial entities (who have the spare cash to tie up funds in payment channels), or for back-and-forth micro-payments by smaller entities who are routed via those larger financial entities (because it is they who have all the channels open, making multiple routes available for someone connected to them.).

And even that second situation requires the assumption that there will be lower fees off chain than on-chain which, if you are being routed through a centralized lightning hub, may not be the case. Because the lightning network is not yet implemented, I imagine it would be impossible to estimate the fees that hubs could afford to charge. (And, of course, if someone didn't use a centralized hub but wanted to use lightning, the average user would have the majority of their funds tied up in channels, which is simply not viable.)

The rest of the conversation centered on what made me more and more confident in labeling the opposite side a "concern troll." They said things like:

You've basically said "It still has the potential to work" - we already know that in theory it can work. I responded on the premise that it was working but when talking practically it is absurdly high risk and therefore not a viable option.

But in order for relying on on chain scaling to be "absurdly high risk", the potential problems would have to be high probability.

Their first response to that point was irrelevant AND wrong. I've put that part of the exchange behind the paywall (for those of you who are extra curious) so that it wouldn't clutter the flow of the relevant arguments here.

His only remotely relevant response to my last made point was:

If the lightning network goes live and is successful the levels of on chain transactions may never reach the levels you described in the first place.....then what would you suggest doing? Limiting the block size? Oops...

Which said nothing about the probability thereof. Only that transactions **may** never reach the levels described in the first place.

At this point the conversation really was a fantastic example of concern trolling, intentional or not. They went on to say:

To start the bigger blocks solution that you've outlined knowing that humanity has literally 100 years to develop a software that will provide instant AND cheaper fees that those on the blockchain - and that the development of this will ruin the network - it's beyond words.

In 100 years we could have people living on mars, but in your opinion they still won't have worked out how to implement a lightning network per its original intention (use for everyone ). Come off it...

But humanity also has that same amount of time to develop optimizations for on chain transactions that could potentially outpace the off chain technologies. To assert that it's more likely that the off chain technologies will outpace on-chain ones is baseless.

The biggest take-away from examples like this should probably be that possibility is not the same thing as likelihood. I can't disprove the potential for an off-chain technology to make on chain transaction volume suffer, the same way I can't disprove the potential for a superbly disguised army to be marching towards my house from the north at this very moment. But I don't consider it likely enough to prepare for, or react preemptively to, and so I don't.

I could of course turn out to be wrong about those low probabilities, in which case Bitcoin Cash (and Bitcoin as described in the whitepaper) might turn out to simply not work as its currently designed. That would be too bad, but the mere potential for that to happen is no reason to plan on it happening and give up on on-chain scaling.