[dmonitor]

Rollback is not a replacement for delay-based, but an enhancement to delay. Slippi, for example, still delays the inputs by 2 frames to minimize the inconsistencies that appear. This can (in theory, not sure if it’s implemented in slippi) be increased to any number of frames to reap the benefits that delay based netcode has. Only using delay is objectively inferior because any flaw that rollback has is also shared by delay. You are welcome to try out the old Melee netplay and compare it to the new Slippi to experience this for yourself.

The reason rollback is rarely implemented is because it is hard to motivate a company to do it when the benefits are so intangible. “Better netcode” doesn’t really sell games, flashy graphics does. And since most of the FGC has existed offline, online is just an afterthought.

This video explains fairly well: https://youtu.be/1JHetORRpfQ

[Firehawke]

That and most developers are in Japan, where rollback doesn't show any real benefit because the infrastructure there is small and fast enough to make even the worst netcode viable.