Companies don't have the infrastructure in place to track former employees and see what they are doing just for the purpose of filling law suits. So unless they create a Unicorn and become famous, they are pretty safe no matter what.
I once heard a VC Pitch from a bunch of patent trolls who wanted to create a company that you could subscribe to called "IP Insurance", that would then track your former employees and sue them when they violated their contracts automatically. With the added bonus that they would somehow buy the litigation contract from the original company so negative PR would be all on the Insurance company.
Couldn't Apple could get into your cloud and see all your data if you use their products?
Only a very small fraction of Apple's employees will ever attempt to be entrepreneurs. It's no threat to the extreme majority of all employees in Silicon Valley. Outsized total compensation and great benefits is all most tech workers in SV are after, entirely reasonably so.
I agree that it will scare off many employees that are heavily inclined toward starting their own thing. It's an interesting question as to whether companies like Apple are better off or worse off in that scenario. People that are particularly entrepreneur-minded often don't make for great employees (I'm in that group).
I don't think I'll ever root for companies enforcing non-compete or non-solicitation agreements. But, if Apple can prove that this guy was working/soliciting for his new company on Apple's time or while using Apple equipment then they may have a case, but it should be a limited case.
No boss, I can't meet that deadline, I'm too smart.
A famous example is Foursquare. Google bought Dodgeball, which was the original product. The founders got paid then left Google and ... started the same company again but called it Foursquare!
My assumption is these companies don't sue because they can't afford the negative impact on hiring. If you thought Apple would own your mind forever you'd never work there in the first place.