I'm a little perplexed that handheld is so minuscule in the graphic for 2022. Where does the handheld Steam Deck fit in?(ROG Ally, etc.) I suppose that could be squeezed into the PC category.
But what about the handheld Nintendo Switch? Isn't that the best seller currently, as a handheld-first? It's not a "console" any more/less than the Gameboy was, though, alternatively, I have seen the Gameboy referred to as a "console" many times. (Corrected by another user, below.)
In any case, why a computer dominates the consoles is not actually all that surprising. First, emulation. It's easy to emulate an NES or Atari 2600 or Sega Game Gear all day. Every new console generation requires once again re-inventing the emulation wheel if it even achieves emulation of older units at all. And often times consoles do not cross-emulate. Playstation can more than likely emulate older PSs, but will it emulate Nintendo Switch? Probably not. PS emulate Gamecube? Probably a thorny topic. PS emulate XBox? Get a lawyer on the phone. PC emulation has had it's legal battles of course, however all consoles are subject to emulation equally once the way to do it is discovered. XBox, being the closest to being an actual PC might be the best when it comes to running emulators of other systems. But when the new XBox comes out there is at least some re-inventing of the wheel required.
Secondly, each console generation is an all-new again environment. Consoles have a limited lifespan of 6, 7, 10 years or so. On a PC you could presumably play Dungeon Master on a brand new machine with an RTX 4090 in it in DosBox and do it again when the RTX 5090 is released. On the console side, the increasingly online-dominant style lets console makers flip the kill switch and effectively destroy the game in total, limiting the game's ability to last for decades upon decades. This is going to get worse as consoles increasingly turn to that online-dominant style. At least I can still grab a Sega CD and play Sewer Shark and it doesn't have a server somewhere ruining the whole thing. To be fair, the server-kill does exist in the PC world as well, but with the flexibility of a computer I do think I remember reading somewhere where fans spun up their own "server" to keep a halted game running, independent and perhaps to the chagrin of the parent company who wanted to kill that game forever.
In both instances the game library generally lasts longer on a PC with the PC doubling-up and playing the role of a "revivalist" for the console who's lifespan came to an end and was thusly thrown to the side of the road by the parent company like a piece of garbage.
Thirdly, PCs will receive "crossover titles". So why buy a console to get the game, just wait for the port. Sometimes. I don't know which is more prevalent to be fair. PC <--- Console, or PC ---> Console. I suspect PC reception is more common as its a bigger market. And. Each console does to some extent operate as a sub-market wheras the PC market is unified. (That is: the Switch market vs Playstation market vs Xbox market, due partially to their exclusives) Or in the end if there isn't a port just wait a tad bit longer and grab the emulator on PC anyways.
Software is king. PC is unlimited software. A console is not.