If governments were more open and didn't try to keep so many secret, it wouldn't be so bad if they got hacked. By definition, if there were no secrets, they'd be nothing to hack. Perhaps this a motivation behind the attacks by Anonymous: they want to show governments that keeping secrets is no longer worthwhile.
I think future governments have three choices: 1. Pay the cost of maintaining highly secure systems to keep their secrets (which can never be guaranteed) 2. endure the costs of their secrets being discovered/revealed by hackers or enemy states or 3. learn to make do without secrets.
It might seem that governments that keep secrets have an upper hand against those who do not. However, this advantage is entirely dependant on maintaining those secrets and maintaining secrets has an associated cost. The cost of maintaining secrets may very well be rising as cracking techniques become more sophisticated. However, by giving up on secrets, you are letting go of the associated costs. Perhaps in some ways you are giving up everything so that there's nothing left to loose. Though if the costs of keeping secrets becomes high enough, nations without secrets may have the overall advantage.