Seems like google could have used some of that 750M to operate at a loss, pay out higher CPMs and attract publishers. It also seems like google could have, in theory, copied their interface or even improved on it. Could it be that google's now too big to make those kind of adjustments once it builds the momentum?
The talent angle of course makes sense, they are both pulling in top tier employees and removing top tier competition.
scenario a:
operate at a loss for a while, maybe achieve target (but maybe not), draw the ire of regulators for anticompetitive behavior
scenario b:
spend cash you can easily afford, have an immediate cash flow return, get a solution that is known to work, eliminate competitive threat without pissing off anyone in the process while ingesting talent at the same time
it's fairly easy to see why GOOG chose the latter option.
The talent angle of course makes sense, they are both pulling in top tier employees and removing top tier competition.