Far more reasonable explanation is that the addressable market for Windows and iOS is much larger and more lucrative - iOS exploits go for six figures whereas L

Far more reasonable explanation is that the addressable market for Windows and iOS is much larger and more lucrative - iOS exploits go for six figures whereas Linux exploits don’t generally go for as much. And exploits for Chrome and Safari go for a lot for similar reasons. No piece of software is likely to really be safe from a super determined and well funded adversary, and that’s why you need ways of structuring things (eg VMs, containers, peer ssl etc) to make things safer. If Linux had anywhere near the market share of those OSes you would see much more publicly the problems of how Debian and other distros choose to maintain those OSes.