If a business can get even a small fraction of its labor to follow unenforcable/essentially illegal requirements, they've made significant headway, even if they don't ever choose to attempt to litigate. Over time, those practices can become normalized and set industry standards where they become more and more successful.
I think it should be illegal to even stipulate such requirements in contracts to begin with to prevent businesses from eroding labor rights over time. There should be massive fines in place that penalize even stipulating those sort of clauses to make sure businesses only include reasonable language/requirements.
1: Yes, I am aware that there are a few software engineers out there with specialized skills who have successfully managed to negotiate some non-salary terms out of their employment agreements. Congratulations, you are not representative of the general employee population.
I'm pretty sure I don't want to be in a position where I'd be fired if a 10-year old lie came out.