Give them twenty more years. Chances are some of them devolve into what IBM and HP were before breaking up.
Well, Apple and MS have already been around since the late 70s and have both shown the ability to evolve without splitting up.
Competent leadership can hold back the tide for a while, but eventually you get incompetent leadership and things go to hell. This is why good democracies only permit authoritarian/oligarchic dictatorships in corporate form, there's no decades of civil war when a bad CEO runs a company into the ground.