Indie game studios still make them. So does Nintendo. They didn't die. It's just AAA game studios turned their budget to making blockbuster level games with shit tonnes of micro transactions in order to make more money because unfortunately they make more money and are generally more popular.
I'd barely say they died. Doom Eternal is full of platforming, something a lot of reviewers winged about, and there are big undies like little kitty big city that fit the bill nicely, as well as the remake of SpongeBob Battle for bikini bottom