I’m a bit curious too. My theory is that it may have come down to licensing and trademark issue. Since the game used actual car brands and their logos and such, they may have had some agreement over their usage and perhaps the period of that agreement ended. It’s worth noting that the game was available from several different stores, and it became unavailable everywhere as far as I know.
Even when that agreement expires (see blur as a race game example), the game typically isn’t removed from libraries.
As for your game I think archive.org has a copy listed ( https://archive.org/details/race-driver-grid_202112 ), it says it’s a GOG copy so it shouldn’t give any issues, does it give any? (Do not click the spam comments, check the download options and pick either zip or torrent)
