I think the phrase "give it time" is useful here.
Honestly, it'd be very hard for a team of developers to realize that what they slaved over to build for years and tune and tweek and bugfix was almost made unnecessary by a protocol someone built in tandem but they really didn't know about it's existence until they were deep in the hole.
But I will bet you that if we wait by the river long enough, the bodies of 'replaced by nostr protocol' code blocks will soon float by.