Jaybeaux, undoubtedly the size of the market...
...plays a role.
I also believe that the Unix platform is much more stable and the work that has been done on top of it has eliminated many of the vulnerabilities. It is not perfect, but patches are released very quickly BEFORE consumers demand it. That is customer service.
Having agreed the size of the market is a mitigator does not mean that there aren't script kiddies out there trying to write harmful code - they are. However, getting it to run rampant is difficult because many of the easy vulnerabilities are not present.
A fortress weathered by time is still a fortress - only wiser.
And the next time I'm near you be sure I will provide you with early warning!