This is such a childish mindset. How much did you pay your plumber to fix your toilet last time? Why didn't you pay 40% more than that?
Likewise, if people on your team get better at their jobs and you don't want them to leave, you also have to pay them more.
You don't pay 2x untill you are forced to (eg plumber is the only game on town) not because you are so enlightened.
My enlightenment comes from talking to a bunch of plumbers and hearing what they're gonna charge. That's the market rate.
If I hire an employee and they get good at their job and someone else offers them a 40% raise, they'll probably leave. That's a lot of money.
Some companies care about retention, most don't really.