Earlier quoted context omitted.
The fact is that "secret sauces" are basically worthless. Every successful business is 99% execution (& luck). A startup, especially in tech, will never be able to base its value on something simple enough for an employee to smuggle out legally (i.e. in their brain).
This is a very biased view IMO. Plenty of businesses are based on patented secret sauces. Even for the type of companies that rely on execution, there will be important lessons learned, which ultimately become the "secret sauces". And you don't fear a random employee who might fit your secrets in their brain. You fear a set of experienced employees who can replicate your businesses somewhere else if they want to.
Secret sauces are, by definition, unpatented - if a business has patented an idea, it is no longer secret, and the success of that company is then partially enforced by the exclusivity of the patent. You don't need a non-compete if your employees have access to patented content, because they aren't legally allowed to reproduce it anyways.
>Even for the type of companies that rely on execution, there will be important lessons learned, which ultimately become the "secret sauces"
Can you give an example of this? I think it's unlikely that specific "lessons learned" could be so valuable. Sure, companies are afraid of losing their experienced employees - but all companies are afraid of that anyways. It has little to do with the idea of a "secret sauce", and everything to do with simple experience.