On chat shows afterwards he used to say he’d never do Spaceballs 2, but he might do Spaceballs 3: the search for spaceballs 2.
I think he’s rightly spotted that Hollywood’s obsession with bankable sequels and the phenomenon of the ‘cinematic universe’ are things worthy of sending up in their own right. And the best way to do that is via a sequel to a film whose main running gag was its own merchandising opportunities.