This is basically one of the arguments why Linux doesn't have as many exploits. If Linux were in more widespread usage, then more focus would be put on exploiting it and hence running it without e.g. anti-virus or other mechanisms would be more dangerous. So Linux's relative market share might protect it more than many security choices in the OS.

(I don't want to claim that any of the reasoning here is true, but I just wanted to point out the parallel to what you're saying.)