Hmm, if he stays in and actually remains competitive, I'm sure Republicans will find a way to pump money to him without looking hypocritical. This is unfortunate - this just gives him more of an excuse to stay in the race.
This looks like a case of "the better it gets, the worse it gets". If Akin can poll competitively for a while (at least until late September, beyond which point I think it's impossible for him to get off the ballot), then he may stay in the race. Yet McCaskill will get an infusion of $ that's bigger than she would have otherwise gotten, and Akin will not get the outside support he needs. Sure, they may pump some $ in covertly, but it won't be as much as he would get in a normal competitive race like this. Plus Akin will get no support from prominent surrogates, because other politicians won't want to be seen with him, and some of his own campaign staff may leave.
Best scenario for the GOP would be poll numbers that looked so bad that Akin could have been convinced to drop out, but the PPP numbers suggest that may not be coming.