This will likely happen the next time a Democrat wins the Presidency, due to demographics. I think Republicans will be in the wilderness for at least a few cycles before they change significantly enough to win a Presidential election again.
You people simply put way too much stock into this. Demographics will always take second place to things like economic trends, scandal, and the popularity (or lack thereof) of legislation passed by the incumbent president/party.
No amount of demographic advantage would save an incumbent who is currently facing a recession. Period.