I would rephrase this as they got there because they treat their customers with respect, they take feedback to improve their platform, they don't pack their launcher / store front with ads and trickery, and you can trust that your games will be there and not go away.
Yes, they are loot box whores but so is everyone else.
Steam is a community, social media, and a store. The community is what they built and that community is extremely loyal. That community is also what developers are paying for.
In Gaben, we trust. I have 20 years of experience saying Gabe won't fuck me over to increase EBIDA by .5%. Are they perfect? No, but they are lightyears better than most of their competitors except GOG in terms of putting consumers first.
This is what I always say about Valve. They are not morally unimpeachable, but at the end of the day I've been a regular customer for over 20 years and they've never fucked me over. I don't think I can say the same about any other software company.
And most importantly, the moment they show any indication of doing otherwise, I will happily drop them.
I keep giving Valve my money because they keep giving me good value for that money and a trustworthy environment to spend that money in. I have no loyalty. I also buy games from Humble Bundle and GOG.
I'm not excited about the prospect of losing my 4000 games but the literal only options available for consumers right now are "Pay money and get a game that we can take away at any time, fuck you over, do all sorts of bad things, and we demonstrably hate you", or "Pay money to get a game and a refund period and a bunch of features and maybe when Gabe dies we will do that other thing"
There is no alternative. GOG is run by the same people who released CyberPunk2077 as a bug ridden mess to please upper management, so they even have evidence of already straddling that line right now.
Going back further, the thing that enabled them to release their first game "when it's done" and set the ball rolling was being founded by two ex-Microsoft with piles of money, most studios don't have that luxury.