It is nice to see that some real philosophers have joined the discussion, I am a philosopher as well. I have constructed a simple argument of my own, you are welcome to try and rebuttal. There has been a lack of rational responses to my arguments so far, and far to much ad hominem and hyperbole. I believe that good philosophy should be simple.
Great! Welcome to the thread. I agree that there's been too much ad hominem and hyperbole. It would be better if, in particular, people avoided accusing BlockStream of nefarious plans for profiteering and accusing Gavin Andreson of being a CIA mole.
I've thought about ways to try to seriously apply logic to the situation. It's tricky. Let's assume everyone on all sides wants Bitcoin to be successful. The problem is that "success" for Bitcoin means different things to different people. We could distinguish them as different predicates: successful(1), successful(2), successful(3), and so on. And beyond defining success, it's possible for people to have a variety of views on the matter: Bitcoin is successful(i) now and we must keep it successful(i). Bitcoin is not successful(i) now and we must make it successful(i).
It might be possible to model the situation using some kind of modal logic or directly with Kripke semantics. There's the world as it is today, and then there are multiple possible worlds* that may follow. In some of those accessible possible worlds, Bitcoin would be successful(i) and in others it would be unsuccessful(i). Different choices about the development of Bitcoin change the world and so change the possible worlds that can follow. It's probably best that I stop here and continue if there's interest or criticism.
*Sometimes people object to the way "possible worlds" sounds and prefer something like "possible states of the world." They're the same in the way I'm using it here.
To put it simply, if we do not increase the block size it will be more expensive and less people will be able to use it, that is to transact on the main chain directly, and instead we will be "forced" to us 3rd party payment processors.
However if we increase the block size then it will be less expensive and more people will be able to use it. Even if full nodes will only be able to be hosted on powerful computers, since miners do not run full nodes, the pools do.
Considering that these would be the most likely outcomes with increased adoption, to me it seems clear that increasing the block size would lead to more decentralization as a whole compared to keeping the restriction in place.
I can go into much more detail of course but I would like to keep it simple in the interest of constructive argument.
It sounds like your primary criteria for the success of Bitcoin is that significantly more people use it than currently do. Is that correct? Would you consider Bitcoin successful if, say, it kept the same number of users as now (give or take a factor of two)?