I had the luck of owning a TI99/4A as a kid; it had a very rich Basic, with the 16k extension cartridge you even had sprites and a synthesizer. I have made some 2d game stuff with pygame recently, and for me it felt as if I got back to this old machine... (here is this stuff, for the record: https://github.com/MoserMichael/pygamewrap )
It was possible BITD too, but no one thought hard enough about how to do it. There has been a lot of "pushing the hardware" over the last decade. Lots of things that were thought of as "not possible" have been done now. The 99/4A community is very active, and there is a lot more going on than just new games (although that is also a big part of the activity).
There are many new developers making games, utilities, new versions of languages, a GCC compiler patch to output 9900 code, a bunch of really cool modern hardware solutions including the TIPI that provides a modern hard disk and internet connectivity via a raspberry pi. and the F18A VDP replacement is on this and many other systems to get VGA out. more info: https://www.arcadeshopper.com/wp/ti-99-4a-faq/
As far as I know the Epson QX-10 / QX-16 is the only home computer system to have never had a game written for it. I've always intended to rectify that situation, since a QX-10 was my first computer, but my current QX-16 system didn't come with a monitor. It uses a nonstandard 40 Hz refresh rate so video capture probably wouldn't work, either (though I've never tried).
What I meant to express is that even though the TI 99/4A is relatively obscure, especially outside the US, it does have a large and active international community.
Its distant and even more obscure relative, the Pyuuta, also has a community, but I wouldn't really call it thriving.
Internationally? I don't recall having seen any of them in Germany in the 1980s. Plenty of Sinclairs and Commodores, even an Armstrad, but nothing from TI.
I got one in Australia with Extended Basic, speech synthesiser, joysticks and cassette. The sprites were next-level cool compared to my friends Apple II, Vic-20 and Trash-80
I wrote a pretty good frogger clone (with only the road part to cross) that worked so well because the event loop was just joystick input and call coinc(all) for sprite collision with the Y axis value of your frog indicating you were in a home base position.
I also wrote a kind of 3 part game where each stage used the full resources of the machine, and each stage of the game required another load from cassette, which normally wipes all your memory and therfore variables so in order to pass variables between the stages of the game I wrote hex values into the extended font/character set memory, because the last few were user editable and retained in memory even after fresh program load (which would decode the hex from the font character to keep your score and number of lives consistent with the prior program/stage of the game).
I had Parsec too of course, but way more fun creating your own games from scratch, or porting a printout of a game from TRS-80 basic and then converting it to use sprites.
Aged 11 to 13 I spent my school holidays mostly indoors learning to code, fond memories of the magic of discovery and creation :)
I can't find any solid stats, but it does seem like most of the sales were US and Canada. And probably a fair amount of those sales after they priced it below cost during their death throes. I believe it was under $50 at the end, which was crazy cheap at the time.
It was our family's first computer in the UK -- pretty sure my Dad picked it up very cheap when the local department store were getting rid of the last of their stock after TI killed the machine. The lack of commercial games for it compared to the Spectrum etc meant I spent more time typing in BASIC listings, which was my first introduction to computer programming...
TI built a ton of them and closed them out at fire-sale prices, and they mostly went into people's closets. It was hard to do much with a base model but play its not-so-great cartridge games so it has few fans.
The fanatics though - there's really cool stuff people do. I think you could cheaply upgrade the memory to 16-bit wide, for example.
Tunnels of Doom was probably my first exposure to Dungeons & Dragons. I woulda played that every day if it didn't require loading from audio tape via a cassette player (a process that was very prone to errors).
Turns out the TI 99/4A has a thriving community and homebrew scene, with two members in particular being exceptionally productive.
Those homebrow games created are even of at least an order of magnitude higher quality than what was available in the 80s.