I find that there are some strange misconceptions here. I will attempt to address some of them in this post.
First of all, the idea that hitting the blocksize limit will just remove unwanted or spam transactions is false. First of all I reject the idea of discriminating between transactions thinking that some of them are desired and others are unwanted. Bitcoin is meant to be a permissionless network, so we should not discriminate between transactions, as long as miners include them in the blocks is all that matters. More importantly however is that once the blocks do become consistently full. It is not the case that you would simply have to pay a higher fee but that there would not be enough capacity for everyone to transact regardless of the fee.
Again, a fee market does not fix this, a fee market simply priorities who is able to use Bitcoin and who is not able to use Bitcoin. There are losers in a fee market that become priced out.
If adoption did increase under these circumstances which I do not think it would, but hypothetically at least. Bitcoin would become a settlement network for larger payment processors, financial institutions and banks. Bitcoin would not be able to be used as a currency directly anymore. Since average people would not be able to outbid these type of institutions for block space. I do question how many people would even choose to run full nodes for these types of larger financial institutions considering that they can not even use Bitcoin directly themselves, it seems counter intuitive if that was the reason for this sacrifice? The vast majority of people would be reliant upon third parties build on top of the Bitcoin blockchain, this would not be that different compared to the system we live under today, with some very important differences granted, however it would not share all of the same and full benefits of the original vision of Bitcoin, which is that it can become a currency for the whole world. Thereby empowering people and fundamentally changing the power structures of our civilization for the better.
I do not think that a limited blocksize in Bitcoin would lead to its use as a global clearing house or a reserve currency in the first place, I find it utterly unrealistic. Since without mass adoption by the people as a currency first I do not see any reason why the current status quo would adopt Bitcoin, since they can design their own systems that they are in control off, which would benefit them more at this point, the only way that I see the establishment adopting Bitcoin on mass is if they are "forced" to do so in order to stay relevant. Exactly because of mass adoption by the people which I believe will not be possible with a limited blocksize, it would simply become out competed by better, faster, more reliable and cheaper alternatives.
Secondly allowing the blocks to fill up thereby overloading the network would make transactions much more unreliable and obviously more expensive, it would also make for a much worse user experience compared to today. This would not be good for adoption, I find it strange that anyone would even claim such a thing, it really is just basic economics.
Further, wallet software User experience is very, very poor in a hyper-competitive fee market.
I also do not consider moving transactions off chain as a solution to scaling the Bitcoin blockchain itself. The main Bitcoin blockchain itself needs to have great value in order to pay for its security into the future. This brings me to my next point.
I find the idea that we must have high fees in order to pay for security flawed. I would argue that it is better to have a high volume of low fee transactions compared to a low volume of high free transactions. An increased price is what would presently allow for increased security, I think that the price of Bitcoin is linked to its utility, by not increasing the blocksize we are decreasing Bitcoins utility which I think would negatively impact the price and therefore also its security. Over the long term we need a high volume of transactions to pay for this security, this also further supports the idea of adoption being critical for the long term survival, decentralization, utility and freedom of Bitcoin.
Higher Service prices can negatively impact system security. Bitcoin depends on a virtuous cycle of users boosting and maintaining bitcoin's network effect, incentivizing miners, increasing security. Higher prices that reduce bitcoin's user count and network effect can have the opposite impact.
It is a valid and rational economic choice to subsidize the system with lower fees in the beginning. Many miners, for example, openly state they prefer long term system growth over maximizing tiny amounts of current day income.
Transaction-fee levels are not in any general need of being artificially pushed upward. A 130-year transition phase was planned into Bitcoin during which the full transition from block reward revenue to transaction-fee revenue was to take place.
Lastly I would like to very clearly state here that Bitcoin is freedom.
While I don't think Bitcoin is practical for smaller micropayments right now, it will eventually be as storage and bandwidth costs continue to fall. If Bitcoin catches on on a big scale, it may already be the case by that time. Another way they can become more practical is if I implement client-only mode and the number of network nodes consolidates into a smaller number of professional server farms. Whatever size micropayments you need will eventually be practical. I think in 5 or 10 years, the bandwidth and storage will seem trivial.
Long before the network gets anywhere near as large as that, it would be safe for users to use Simplified Payment Verification (section Cool to check for double spending, which only requires having the chain of block headers, or about 12KB per day. Only people trying to create new coins would need to run network nodes. At first, most users would run network nodes, but as the network grows beyond a certain point, it would be left more and more to specialists with server farms of specialized hardware.
The current system where every user is a network node is not the intended configuration for large scale. That would be like every Usenet user runs their own NNTP server. The design supports letting users just be users.
I’m sure that in 20 years there will either be very large transaction volume or no volume.