Since the tariffs they are on are protected for the first 20 years then probably all that would happen is that the offers for free panels will dry up. They will then stay operational to collect the tariffs they have already as Steve mentions above.
As far as I was aware micro inverters are only really useful if some of the panel is in shade. If the whole of your setup is in direct sunlight (like mine - facing exactly South) then there is no need for micro inverters. My panels are great. Just installed a solar iBoost and buddy (great bit of tech) and have just ordered a Renault zoe as a second car!!