It's not the start of a massive shift. You'd be surprised what the gaming spending per platform breakdown looks like - phones are a MASSIVE chunk, and growing by far the fastest.
I don't have the numbers on me to back this up but maybe someone else can fetch them.
The rule of thumb when it comes to sizing gaming audiences is:
- Mobile: Billions
- Console: 100s of millions
- PC: 10s of millions
In other words, a decent mobile game (not Fortnite or LoL, but something like Among Us) can get 100s of millions of users, a good console game can sells 10s of millions of copies and a PC game can sell millions of copies.
According to one source[1], steam alone has 95 million monthly active users. Not every pc gamer has steam running, so actual PC gamers are definitely in excess of 100 million. By comparison, ps plus and xbox live have 103 and 90 million monthly active users respectively. I'd say that PC and console gaming are within the same order of magnitude.
10's of millions of PC gamers? I think you're off by a huge margin. I believe DFC reported that there's over a billion PC gamers in the world in 2020. It's a billion dollar market in itself.
I don't have the numbers on me to back this up but maybe someone else can fetch them.