How do you plan for the future when nobody can accurately predict the future? I remember where it was claimed that OOP UI api's could "last forever" because they were an abstract interface rather than implementation. However, they couldn't handle the stateless-ness of the web because OOP is inherently stateful. It's almost like having a printer API that assumes a color printer, and suddenly it's being asked to translate into black and white. You'll lose output meaning without reworking everything. Abstraction usually has to make assumptions, and these assumptions may turn out wrong down the road.
Re: no one wants to budget for those activities
True. That's one thing an org can and should plan for: money to pay for upgrading. In other words, you cannot predict future technology, but you can safely predict that adjusting to the future requires resources the vast majority of the time.