To continue: Satoshi's narrative of "let's keep small blocks as long as we can, later we'll switch to big blocks, but first we have to trick people in this thing while it is small", and his code example, would have prompted, if he were honest, to indeed, include this if statement:
"small blocks until block number X". The fact of not having included this, even while he was saying that one COULD do it that way, and given all comments, indicates he wasn't being serious here. You can say: "hey, but Satoshi couldn't know how bitcoin would evolve, at what pace, so he didn't want to commit anything" ; but then, he didn't back away from programming an emission curve over 140 years, without knowing how it would evolve either. If you feel secure enough to program an emission curve, you for sure can program a block size limit. In any case, it doesn't hold water: "a constant in the protocol one should change later" is not easier to change than "an if statement one could change later". Both are protocol changes. In as much as you claim that you put in the constant "only temporarily, and you guys should remove it later", you can just as well commit that "temporary" aspect in an if statement right away ("and if deemed still to early, you guys should modify it later"), putting your code where your mouth is. He didn't.
So the Satoshi in 2010 clearly wanted it to be a permanent thing, knowing that it would give huge problems at a certain point in time, totally contradicting his November 2008 statements, but claiming otherwise, that it is only temporarily and doing lip service to his 2008 statements at the same time. Because the OBVIOUS response, in agreement with his own statements, and with all premonitory remarks, would have been to put an if statement in the code. He even says so, and he doesn't. He only shouts at the guy that wanted to remove it, he tells us that one should put an if statement, and he keeps a constant "to be modified by an if statement later".
As discussed above, you can always use a more severe soft limit during mining, than the hard limit in the protocol. But you can't remove a hard limit in the protocol without "breaking compatibility with the network". So if you're honest about admitting larger blocks later, you should foresee in the code to remove the protocol limit "later" already NOW. If you don't, you're simply lying. Especially if you explain it.
Also, in as much as hard protocol constants "could be changed on the fly", nothing stops you from modifying the constants that determine the emission curve, the difficulty adjustments, and so on. It is totally incoherent to claim that a constant in the protocol can be modified at will later and think that you are going to make a system that is going to be accepted as immutable. If you can modify the protocol parameter of hard block limit, you can just as well change the protocol parameter that gives the block rewards, or the halving blocks or anything of that kind.
So, yes, after re-reading that 2010 thread, it is now clear to me that Satoshi didn't "make a mistake". He put a bomb in his system. I only realized this now, but it seems evident after all.
One can say: maybe he realized that his 2008 scaling solution was going to "centralize" is system, so he simply put in something that would push people to invent an off-chain way of using it. In other words, he put in this limit because he understood that block chain tech doesn't scale, contrary to his 2008 explanation, and considered that people should invent something that solves it in another way. In other words, he did this to push people to invent the LN.
But that doesn't hold water either. Given that he didn't know whether something like the LN could even be invented, and given that he didn't know when it would be invented, and what would have been its needs, crippling the only solution you have, of which you've explained how it would scale, would have been extremely dangerous. If the LN would only have been invented in 2025, bitcoin would have been dead already by the time it could have been invented. That's akin to jumping out of an air plane, and hoping you'll invent a parachute while falling.