Every person excluded from a purchase is money lost in the eyes of corporations. It's why boycotts work when they're properly organized. It's why microtransactions are usually less than $5. I've been in corporate meetings for game companies before, I was recently illegally fired. The addition of Linux support is coming, but the big corporations need motivation to do it quickly.
You have to compare income from sales to development and ongoing maintenance cost of supporting a whole other platform. Not all engines can easily build for Linux. And the ones that can, are sometimes hindered by windows only libraries, which may significantly speed up development or quality of the game.
Boycots work when the market share of boycotters is significant.
As with your arguments where you mixed relative and absolute numbers - you can not apply the learnings of one subset of game devs (yourself & the companies where you worked at) to all of them, as they operate in vastly different circumstances.
I was illegally fired for organizing unions. The labor activist world is tiny. I'm able to make these statements with the confidence that I do, because I've talked to hundreds of people in several game companies.
I don't think you understand the outsized influence a few hundred activists can be. I was 1 of about 30 people who helped organize AQAU, one of the biggest unions in the industry, 600 people encompassing all of publisher-side QA.
Just hit me up when your prediction comes true and I'll happily agree that you were right all along. But looking at historical trends and the data that we have on the matter today - I can not share your confidence.