I mean, that's the weird dynamic of requiring manpower with rare, valuable talents. They often have quite a bit of money, already, and they have comfortable options for where to work to get more money, so you either have to offer them MUCH more money (if you're rich) or you have to offer them some incentive that they value more than "more money".

Non-monetary incentives are actually more sustainable than monetary ones, but they're more rare and complex than money. They are, essentially, things they would happily work to attain, that they can't easily purchase with any money you could give them. Friendship, romantic love, access to some specific territory or group, knowledge, privileges, etc.

So, you can end up with two people wanting the same manpower, one rich person offering €100k/year in full-time, for a limited time, and one poorer person offering €0/year in part-time, for an indefinite time, and the latter offer is much more attractive.

Money, in other words, is useful for buying things you can buy with money, but not everything can be bought with money.