I might be a great telecomm tech, a genius even, but once I'm out of a job, I can't build my own telecomm system - that would cost billions. I have to go back to some other telecomm system to start making money again.

But, at a startup, a kicked-out senior engineer can actually pretty much exactly recreate the company; they can do the equivalent of a laid-off telecomm employee starting a new, almost-as-good (except for branding) telecomm company.

No billions in infrastructure required: within a month or two, the cloned company could be near-indistinguishable from the original.

So companies have to pay employees more like partners, instead of employees, because either they pay them as equals or they'll be forced to compete against them, as equal rivals.