Rocket League supported modders and mappers before, even having Steam Workshop support. Since Epic got involved, they’ve only cut down on mod/map support.

What’s crazy is the numbers are basically double the pre-Covid numbers. Meaning half the players on Steam today weren’t there before 2020.

Publishers used Steam for physical releases because Valve takes no fee for CD keys, so it was cheaper for them.

the number of windows pc users has been plummeting lately, and it’s not in favour of linux but mobile os’es

Non-gaming PC/Windows users are going down, but PC gamers are at all time highs and still growing.

Does Valve refuse to allow third party stores to sell Steam codes like PlayStation is doing here?

In the US maybe, $100k is several years wages in many countries.