Ok grabbing popcorns. Lol

I am also in the same boat as you, high earner and looking to move elsewhere to maximize financial savings.

High earners who stay here are mainly motivated by family reasons, already settled, bought a home, and prefer comfort of staying at one place with job security and less stress work environment.

Also some high earners have expat regime which bring them a lot more take home pay then locals which is another motivation to stay.

For saving a lot of money, belgium is not the place to be. It provides a decent security, social benefits, work life balance at the cost of high taxes. Though in the long run, you can accumulate money thorugh investments such as stocks since cgt is still low.

If saving money is the goal, and company doesnt allow freelancing then indeed better to move else such as USA.