Prices for retail games have not got cheaper over the years, so a free market will put its money towards trusted names. Video games are a medium that isn't cheap enough to take gambles often. Nintendo is the most trusted game publisher for good reasons.
Since the latter half of the 2000s there has been a general trend of the middle falling away. Nowadays you have AAA publishers, then a lot of mostly nothing and lastly, small publishers. The overall number of retail releases has decreased over the years, so the heavily advertised games on all consoles can rake in more sales because the amount of visible competition has been getting smaller over time. That is, as long as the installed base of a console isn't an obstacle and limits how much games can sell. The Wii U is an obvious example of a console that held all the games back, but Switch doesn't suffer from a problem like that.