Author here. I got a big bump from $230K to $396K in 2016 when I got a competing offer and Amazon matched it so that I wouldn't leave. From then on, the growth from $400K to $500K happened because the AMZN stock nearly tripled in that time frame.
I do share the same sentiment as yours. I'll be closely watching your experiment and hopefully learn something from you!
Good luck and best wishes!
By that logic hires are bad deals if they ever eventually leave because you "lost" the money of their last n years.