We are truly at a "wait and see" stage here, and the Allegorithmic guys deserve the benefit of the doubt. Every possible question and speculation has been covered in this thread. The deal is done so let's just wait and see how it shakes out. 
Yeah, I would like to do that - but the 'Allegorithmic guys'
are not in control any more -
Adobe is. Read the bottom of this web page '
Substance by Adobe' - Allegorithmic no longer exists.
Adobe
only has the SAAS business model.
If the perpetual model remains for Substance painter it will likely only be for the version current before the take-over.
I am pretty sure it will all be a good thing if you like the SAAS model. But if not, learn to love your current perpetual version, it is likely to eventually be a dinosaur.
And you are right - the deal is done - we have no option but to see what happen.