"Chip vendors would not give Google the blobs and Google would not waste their own time maintaining firmware for devices they didn't produce. Google might as well produce all the devices themselves which they don't want to do."
But they may HAVE to do it. Think about it. The Stagefright exploit is in the Android code, not the driver code or anywhere else, but in the part of the code that belongs squarely to Google. If the lawyers play their cards right, they can assert that Android is not fit for purpose unless Google can find a way to get past the manufacturers and patch it and anything else that comes along. Either Google has to FORCE manufacturers to send updates (which they won't as they have perverse incentive NOT to; they'd sooner drop out), they have to take control themselves, or Google is likely to face severe civil and maybe even criminal liability. Ask the bean counters which will be worse for the bottom line.