So what do you suggest they should have done? Traded their top players to keep their depth? The cap exists; they couldn't keep those guys. What's happening to the Bolts is the same thing that has happened to every championship team in the cap era.
Funnily enough, letting most of those guys go proved to be a good decision in hindsight. Of all the guys who were let go after the Cups (Gourde, Goodrow, Coleman, Palat, Killorn, McDonagh), the only one still performing up to his contract is Coleman (arguably McDonagh too, but that cap hit combined with that age is a bit scary).