Then it is a poorly written contract, and the party that agreed to it was tricked or poorly advised. Plain and simple. We see this often with "fast and loose" term sheets for some corporate and sovereign bonds on less reliable names. There is a whole podcast (I forget the name at this very moment) that does nothing but discuss dubious bond contracts. Frequently, the co-hosts will ask: "Who in their right mind would agree to such a contract? This clause is totally unenforceable / provides no protection against event X/Y/Z." And, yet, these contracts still exist in the wild.

Dumb question: Do you think the average dev in Silicon Valley pays a third-party employment contract lawyer to review the terms and conditions before agreeing? Sadly, I feel the answer is "no". Speaking personally, I would never agree to such complex employment compensation terms without third-party advice. Yes, I know it is not cheap (maybe 500 USD per hour), but the alternative looks much worse, and most people here facing these contracts can afford it.