The article indicates some of them will - they predict that if Newt drops out both Romney and Santorum will get some of those votes.
What they don't say is what happens to Newt if Rick drops out. If all of Rick's support would go to Newt, he'd have an even bigger lead over Mittens than Rick would have if Newt left.
Why would Rick drop out? He’s won 10 states, came extremely close in 4 others which he lost by slim margins due to the split vote (two of which are key states this fall), and is polling better than Newt in all the upcoming contests. He’s also polling better than Romney in some states, and polls show he does as well (if not better) than Romney against Obama. He certainly does better than Gingrich. If it was flipped, I’d say Rick should drop out, but it’s not.