I don't have reason to believe that the GOP would do any of these things with a supermajority.
Since I'm feeling hopeful:
I don't think the current GOP would fix entitlement spending with a supermajority.
However, the most popular political party in the country right now is the Tea Party. The group most specifically concerned about fiscal responsibility.
If we do not reign in government spending, our country will collapse in the next (
WARNING! Economist predictions! Take with a grain of salt!) 30 years. Possibly into Argentina, possibly into Weimar republic. Those 30 years will be faster if we continue to grow spending.
However, like most of our problems, other countries will get there first.
What I'm afraid of is: What happens when the backbone of the world economy snaps? We're talking fall of Rome level of societal collapse.
I think the Tea Party's popularity is a result of citizens recognizing this. If this anger at spending finally gets traction with the public, we
may elect republicans who WILL cut spending. (Democrats are genetically incapable of cutting spending.)
There is hope. It is not yet a surety, but at least we can see it is possible.