Actually yes, that IS the last thing they would want. They do not want several parties to oppose. This is a two party system. There have been two times in this country's history when a major party collapsed, and it was shortly replaced by another major party.
The first time was the demise of the Federalist Party. What happened was that the former Federalists joined the Democratic-Republican Party, so the primary actually determined who would be the winner. That led to the spectacle of John Quincy Adams running under the Democratic-Republican Party label even though he was basically a Federalist in outlook and the Democratic-Republican Party was Jefferson's Party. It was after that when Andrew Jackson reformed the Democratic-Republican Party and the Whig Party fissioned off of the Democratic-Republican Party, picking up the torch from the old Whig Party.
The second time was the demise of the Whig Party. It was very quickly replaced, less than four years later, by the Republican Party, and the Whigs basically changed their party registration.
So what does this mean if you actually think the Democratic Party won't save the Republican Party? One of two things.
If we go the first route, many current Republicans will change their party registration to the Democratic Party. That means Democrat George W. Bush. That means Democrat Sarah Palin. And you won't be able to say "you're a racist" as an automatic rebuttal to those who disagree with you because that only applies to non-Demorats. What will you say to Democrat Dick Cheney? You will have a vastly larger party, with a hard right wing, until the party fissions again.
If we go the second route, many current Republicans will simply change their registration to that of one of the right wing smaller parties. However, like with the Whigs and the Republicans. this new party will have a lot less baggage. It will be difficult for many of the current attacks to work as any former Republican can say "those were the Republicans, we aren't Republicans."
So, which do you prefer? I can tell you that neither of those options are attractive to the leaders of the Democratic Party.