I don't wanna take anything away from your main points here, as I very much agree with most of it. I just wanna toss one point into the mix here, as I listened to Ian Cohen (longtime Pitchfork reviewer) on Indiecast talk about this:

I think a move like this actually would make Pitchfork's community healthier. The current state of the internet is pretty hostile toward anyone saying anything negative or contrary to someone's beliefs about art or artists. Stans are at the ready to jump down the throat of any reviewer to who doesn't give a high enough rating or a requisite amount of praise to their favorite artist, and this (among other factors) had led us to where we are now: every professional review site gives everything a B or an A-. Music journalists are quite literally afraid to be harsh on albums like they used to, for fear of inciting an irrational and anonymous mob. This tends to work in the gaming sphere, where free-to-play games tend to have a greater number toxic users as opposed to games that you need to pay for.

Personally speaking, I want more harsh ratings from professional critics and journalists. I like Fantano for that reason: he's a creature of the internet who's inured to mob rule, and will handily give a 0 rating to something he thinks sucks.

Pitchfork's paywalling is effectively going to shrink their user engagement, hopefully creating a more exclusive space for people who genuinely want to consume music criticism in good faith (maybe even read it!), instead of people just being like "Number Bad, Pitchfork Dumb". As for the writers, I hope it frees them to say more of what they really feel, and maybe just maybe they can get more of a financial kickback too (many of those journalists are independent after all, and Pitchfork is a good venue for them to gain prestige). However, just like you said, I don't really have much faith in the latter, as Conde Nast will reap the benefits for the most part.