Valve just has a lot of goodwill, they don't feel the need to comment on every social issue, they censor less than the competition, they are very indie friendly

Valve just has a lot of goodwill, they don't feel the need to comment on every social issue, they censor less than the competition, they are very indie friendly, they'd rather just not put out a sequel than churn out yearly releases, the tech they have put out has been (mostly) innovative and still retains popularity. They also have the goodwill for helping make gaming on linux practical enough that there can be a handheld gaming console that runs linux (plus, of course, popularizing that entire new market segment). They also don't constantly change large parts of Steam. Point is, people like that Valve is relatively stable, and that's why they insist on sticking to it. The industry is otherwise such a shitshow. The stability is an especially important value for a platform that holds, in many cases, thousands of dollars worth of games for people.