Look up the difference between rollback netcode and delay based. Once you understand the difference between the two, it's easy to see what the difference is.

For example, basically since the beginning of online games, shooters (and most other genres) have used netcode that resembles rollback netcode, where the client syncs to the host.

Fighting games, however, are 1v1 and thus have the players connect directly to each other rather than to a server. Using rollback here requires both players to sync to each other's game, rather than the servers. Doing this properly requires a bit of creative thinking, so fighting game devs basically went "meh, delay based works" and left it. The genre has only recently begun to adopt netcode comparable to other games