It's interesting how people expect workers to "earn" their salaries through suffering. It's almost religious. At the same time, lots of businesses charge their clients a percentage of their earnings and it's ok.
The employer earns my work by giving me a salary. My work has a value and the employer pays for it.
The minute they stop paying me, my offer cease and they lose any future value I might have brought them.
Maybe it's because I did a lot of freelance and agency work before working a full time contract.
Over here (Montréal) there's right to work laws and precedents that makes it so that those clauses are pretty much null if they keep you from working.
Non-compete pretty much only protects the employers from having a direct competitor recruiting their employees.