So, who defines "unused account"? I mean, I see your point in this instance, but who wants the chore of logging in to all their accounts every 6 months (or more often?) just to avoid losing them? What if merely logging in becomes "not using it enough" for some services?
If you hadn't logged in for a few years why would you expect it to still be open? It's a perfectly reasonable policy to recapture unused accounts.