This is all very true but it can be addressed by making an increase in difficulty a necessary requirement for an increase in the blocksize limit.
It seems like a reasonable thing, not sufficient on its own but reasonable... (in fact!) I've previously proposed it myself. (not sufficient, among other things that it doesn't do anything to keep incentives aligned, or keep centralization gains moderate.)
Now for under 20% of the cost of an iPad one can purchase a used laptop running GNU/Linux that is perfectly capable of handling a full Bitcoin node. If the 1-2% of Bitcoin users
Yes, but thats only true for a certain set of limits at a certain size. 100MB blocks wouldn't be tolerable on thrifty resources like that today. You may be making an error in reading my message as some kind of opposition instead of tradeoffs which must be understood and carefully handled.
True but this is essentially self defeating. If it turns out that a centralized or semi centralized solution can be competitive with Bitcoin in certain situations then so be it. This however should be a result of true market forces and not an arbitrary limit placed on Bitcoin.
Centeralized services are inherently more efficient, enormously so. My desktop could handle 40,000 TPS with a simple ledger system, giving nearly instant confirmation... physics creates limits for decentralized systems in scale and latency, and thats okay the decenteralized systems are much better from a security perspective. My point about there being alternatives to increasing scaling are not limited to (semi-)centralized systems, though they're useful tools which will exist in the ecosystem, there are decenteralized approaches as well.
I also think it's wrong to think of semi-centralized systems as being in competition with Bitcoin, if process transactions for Bitcoin value they're part of the broader ecosystem; and Bitcoin's trustlessness should enable semi-centeralized systems which are far more trust worthy than what is possible in semi-centeralized systems absent something like Bitcoin. We should be able to adopt them in the places where they make the most sense and have the least risk, rather than try to force all of Bitcoin to the level of centralization needed to make processing $0.25 coffee cup purchases economically efficient while still doing a poor job of it.
Edit: With respect to CryptoNote and Monero, I do see merit in the argument that the fee penalty alone may not be enough to constrain blocksize; however when combined with the difficulty increase requirement the picture changes. As for the specifics of the Monero blockchain there are also other factors including dust from mining pools that led to the early bloating, and we must also keep in mind the CryptoNote and Monero also have built in privacy which adds to the blocksize by its very nature.
Yes, its complicated but it's also concerning. The only altcoins that I'm aware of which have diverged from the current Bitcoin behavior in this front, and did so with the benefits of all the discussions we've had before being available to them, have been suffering from crippling bloat. That they have stronger privacy features which make transactions somewhat larger is somewhat relevant, but the average mixing size on monero is small.. and we may need to adopt similar functionality in Bitcoin (esp as increased mining centralization, partially fueled by the cost of operating nodes makes censorship more of a risk). This doesn't prove anything one way or another, just something to think about the way it was originally presented sounded to me like you were saying it was solved over there, but instead I think that the experience in Bytecoin and monero brings about more questions than answers.