We do not know Native Instruments' plans, but NKS will presumably keep working on VST2 in Maschine/Komplete Kontrol even after VST3 is added, or perhaps they'd update their spec to use VST3. In either case I don't think there's cause for worry.
Eventide plugins all offer VST2 and VST3 versions. At the moment, only Blackhole has NKS support.
