Well, not all of them, since a ton of professionals use them, but some niches like PC gaming will feel a bit like that very soon, compared to mobile gaming.
https://www.statista.com/statistics/292751/mobile-gaming-rev...
(and the trend is for mobile games to become much bigger much faster than desktop games)
I suspect the hobby scene will be like what I see from my friend who hacks keyboards, special mod-able components. There's advantages for when a product is designed on hobby merit, and I think it'll be a longer bastion of enthusiasm.
Sure mobile gaming is massive. But considering the current growth of PC gaming it's hardly something that negates the existence of PC gaming even if it's smaller in comparison.
They heyday of PC games from a market share perspective was in the past (probably around 2005?). At the time there were just PCs and console, I think they were reasonably close.
Now desktop games are less than a third and they will probably be around one fifth or less within a decade.
That doesn't mean that they will be bad, the overall PC game market value will grow, it's just that the mobile game market will grow much faster and become much, much bigger over time.
[1]https://www.guru3d.com/news-story/microsoft-to-share-more-de...