Yeah, I don't see any chance for victory. Obama has been a successful president, and the electoral map has simply moved away from the Republicans. I wouldn't be surprised if the GOP doesn't win anymore presidential elections. I think Romney would really be an amazing president, but it looks like we won't get a chance to see. I just hate to see pbrower win.
It is far too early for the Republican party to be written off like the Federalists or Whigs. To win any later Presidential election it will need a new coalition much broader than what it now relies upon. The acid test for the Republican Party will be in 2016 when it has a raft of Senate seats to defend -- most of the winners of 2010 and maybe some that old guys (most likely Grassley and McCain) vacate. Even if a Republican (let us say Bob McDonnell) wins in 2016 he will have a difficult time pushing a "conservative" agenda whenhe gets little cooperation from a large D majority in the Senate.
The Republicans survived the FDR era after losing control of Congress in 1930 and the Presidency in 1932... but it took them until 1946 to win back Congress and until 1948 to have a real chance at the Presidency. No way is Barack Obama quite up to the level of FDR as President, and no way is he getting any Third Term. But remember -- the Democrats and Republicans were long very similar on the whole. The Democrats had John Stennis and the Republicans had Jacob Javits in the Senate at one time. In the early 1960s the Democrats were a liberal Party in the North but a semi-fascist Party in most of the South while the Republicans were a conservative Party in the North and irrelevant in most of the South.
If the Republicans can't broaden their coalition they are doomed. Most likely the Democratic party does what it did after it became the only major Party with the demise of the Federalists and Whigs: it will split. Single parties are almost always too unwieldy in a democracy. (I predict that the ANC in South Africa will eventually rift). The Whigs initiated as a rift from the Democratic Party of Jefferson, and the "Free-Soil" Republicans rifted from Jacksonian Democrats.
Ideological extremism is not good for winning more than a couple of elections. The Democrats would be in deep trouble, for instance, if they adopted a Marxist agenda. But that said, the Republicans could still win the Presidency in 2016 -- but they will need a much broader coalition with which to win. Part of that coalition might be a segment that the Democrats serve less than well.