Most people who buy your game won't play it

I think there are more possibilities than simply hoarding.

A game might be conceptually interesting enough that I am willing to toss a few dollars to the author as a show of support for their effort (particularly when the discount reaches >75%) even if I know full well that it will likely never quite reach the threshold where I find it interesting enough to install it and try it out.

For other games that are mostly story rather than gameplay, I may already have experienced the content elsewhere; e.g. for Slay The Princess, I watched a playthrough by an online streamer and found the experience interesting enough to purchase the game as a show of support to the creators.

The issue with "The number of games you have played" is the card collecting. Right now ArchiSteamFarm is running on my laptop and is 'playing' games to farm the cards. Cards which I will sell around the Winter Sale and that money will buy me a game or two. It's also the reason that the "Year in Review" stats which Steam produces are, for people like me who farm cards, are fairly pointless. Amusing though. I do get that the stats are useful for people who do not farm cards.

The other issue around the 'buying' of a game is bundles. If I see a bundle in which I want one game and not the others then if the bundle price is lower that the wanted game price, and it always is, then I'll buy the bundle. I might redeem the other games to my account for card farming, but I'll gift to Steam friends if they want them.