The problem was that neither had any reason to drop out. The voters never really liked Newt and Santorum was never really a good candidate.
Santorum thought "I can't drop out for this guy, people just don't like him." And Newt thought "I can't drop out for this guy, he's just not a good candidate."
The problem was, they were both right.
To a certain extent, I would agree completely. If it were a two man race. In our particular scenario, two man logic doesn't apply. Mitt was always the man to beat. Any calculation had to factor him in first, and others second.
Rick and Newt may have accurately assessed on their own that the other guy was a flawed candidate in some way. Fair enough. They're both flawed candidates. But the point they should have been looking at was, 'is the other conservative guy in the race better than Mitt Romney?'
Now Mitt has the initiative, and the conservative side remains fractured and divided. Since nobody is going to drop out, our side will remain fractured and divided, and Mitt's initiative will translate into inevitability.