Apple was estimated to account for over 5% of worldwide desktop/laptop market share in 2011. This barrier was a significant one to break Linux maintains under 2% market share and Google ChromeOS even less. The delay in Apple malware until now most likely was not because Apple exploits were unavailable, or because the Mac OS X system is especially hardened. Speculating that eastern euro-cybercrime is behind the botnet would be a pretty confident way to go right now. We dont believe that other sensitive data has been targeted.”]
Source: https://securelist.com/os-x-mass-exploitation-why-now/33808/