But yeah, "not available anywhere else" can be implied to mean "for sale by the rights owners" and that's fair.

Not really true. For loads of classic games....and this might come as a shock to you....there are no rights holders.

There's uncounted games where the Dev company went out of business, so they don't have the rights. The publisher of these games also can go out of business. The original devs can attempt to get rights to their game before all other holders are dissolved, this isn't always possible.
This leaves the used market. The used market where there's one major valuation company, who has been verifiably manipulating the "collectables" market so that the owner and his pals can make an absolute metric shit tonne of money selling off their games.

On top of all that other bullshit. As if all that wasn't enough. Physical media degrades over time. So even if you manage to find an original dingdongdoodle box, and a cartridge for fiddlefart9000 that you loved playing as a kid.....both the original hardware and cartridge could be completely fucked due to age, expired electrolytic capacitors leaking and destroying all the traces and chips, humidity destroying all the traces and chips etc etc etc etc. And you might pay $1mil for it.

Edit: also.... maybe we should both look up the definition of pedantic, because I'm pretty sure what you were doing wasn't pedantry, but being incorrect.
Emulating modern games, sure, knock yourself out, but for classic games there's often literally no legal(in most parts of the world, regional laws often have little to do with American law) way to acquire or play them.

Theres still a way for a handful of enthusiasts to play games using retro hardware, usually at a huge personal expense. Not everyone could, as there are extremely limited numbers of these consoles and games available now. Not to mention the collectors who argue that any of these consoles that still run should be preserved for as long as possible rather than be used to play games.