I think what has been missed is the parameters for the attack has changed, Windows PC used to be prime targets due to their large market presence, the prime use of an infected PC was control, so the PC itself can be further utilized in other activities which may prove more profitable, info stealing capabilities were later added, but this caused unnecessary bloat given the primary role of infection, given a few hundred compromised PCs only a handful may have profitable info.
Now the demographics for a Mac user is completely different, doesn't take a genius to realize Mac users tend to have more financial leverage, they are also less guarded about storing sensitive information and significantly less likely to have security software, sure there are less of them but the chances of profiting from each one is far higher
a really smart malware programmer targeting Macs would not create something big and bloated that tries to get everywhere slowing the machine down sending out large swaths of information trying to always connect to the internet, he would create a small stealth instrument which remains hidden and imperceptible sending out very precise and select pieces of information, in short the Mac user would think that they were not infected, for the malware author maintaining the status quo would be their most important weapon