That's the problem with these rides. Your kids will eventually outgrow these as well. Fantasyland, meanwhile, have rides that nobody outgrows. Even the oldest person can still enjoy Alice in Wonderland or Peter Pan's Flight.
Nothing in Disney Park should be outgrown.
Walt Disney wanted a place where children and grown ups can have fun TOGETHER. Yes, parents can still ride the rides in A Bug's Land but do they want to? No.
There's plenty of places for the little little ones:Adventure City, Camp Snoopy at Knott's, and Legoland.