Why were there so few and what were they anyway?
Minecraft kind of started it. Maybe Roguelikes such as Nethack? They certainly had the survival elements, although were much more brutal. That’s as close as I’ve ever seen that could be comparable to Minecraft or survival sandbox games prior to Minecraft itself. It feels like if it did exist, it would be known by a Euro gamer; all the crazy cool complex games from really early days of gaming I have found were made in and popular in Europe, but didn’t see much action here in the states.
Infiniminer came before Minecraft and was what directly inspired Minecraft. Off the top of my head UnReal world comes to mind as a survival and sandbox game in that vein and it came out in the 90s. It wasn’t a super popular genre at the time.
The closest games that come to my mind are Schiffbruch and Stranded.
Terraria, though similar release date? Highly recommend the don’t starve series a few years later. It’s quite different as far as game play though.
I played the shit out of Garry’s Mod before Minecraft was a thing