You want those people specifically. To get them, you need to hire them for a lot more money than you pay your current folks. That causes a lot of resentment with folks and messes up things like salary bands, etc.

But since they own equity in the current company, you can give them a ton of money by buying out that equity/paying acquisition bonuses that are conditional on staying for specific amounts of time, etc. And your current staff doesn't feel left out because "it's an acquisition" the way they would if you just paid some engineers 10x or 100x what you pay them.