You have to use some operating system at the end of the day, and vulnerabilities can impact any of them. You might as well trust Apple as much as the next company, since all of them are liable for millions of lines of code, and it's likely they all presently have undiscovered vulnerabilities.
Not sure what you are asking? As far as I can tell, hackers hack like fish swim. We just do. For a multitude of reasons.
For many people, me included, if you wanted to give me a bunch of money to do something and I bit, not that I would nowadays, that could actually lead to a loss of motivation.
As for vulnerabilities, many open source projects responds to them much quicker that industry. Say for pride in their work. as one motivation.
Pride can be fleeting. There's certainly advantages and disadvantages to depending on security patches from a paid organization and from volunteers. Regardless of which OS you use, you will need one that regularly patches its vulnerabilities.
