Feudalism was an evolution of the old "agrarian empire" concept. Technologies to easily transport large quantities of goods were still hundreds of years away. So your kingdom could only get as big as the economics of transport allowed. You could gain political control over a distant land and exact tribute, but you had to visit the area regularly with your imperial army or they'd stop.
Ruling classes were limited in just how much they could take from the surrounding areas. Localities developed cultures and social institutions like English common law, and the ruling classes universally realized that it was more useful to work within those traditions than it was to impose your own on them. Where they conflicted, religious authorities were there to mediate disputes. Out of this reality, feudalism arose and developed for hundreds of years. Local people didn't have the means or inclination to do foreign policy or state building, for the most part. Lords were the necessary evil they accepted so that they could get left alone.
Naval technology changed all that and created a new merchant class. It became economical to move large quantities of goods over water and the people that did that quickly became rich. The original merchants were royally chartered, but there soon was enough of a manufacturing base in naval tech that anyone could start speculating in commodities.
Thus began colonialism. The old land lords lost power and prestige to the new merchants and slavery, which had been gone in Europe since the Roman Empire fell, started to serve the new colonial masters, who were far away from the old systems of social control, church and state. Wealth became liquid in a way that it never had been before.
It wasn't so much the forced work that was the problem, but the transportation away from home communities and the treatment of people as commodities. Britain proper long abhored the slave trade even as British citizens participated in it. International law had to be wrapped around the seas, and the British slowly brought a stop to the slave trade, at great expense. Slavery in her former colony took a civil war to end.
Forced labor can make individuals rich and powerful, but it's free people and institutions and the deals they make and the social contract that provide for the advancement of nations. Slavery was an existing part of the social contract under the Romans, then it didn't make sense anymore, until technology made it possible to bring it under the yoke of individuals.
As a nation, we're slowly coming to terms with the need for new social contracts to provide for the common welfare. Gig work allows individuals to be economically useful that wouldn't otherwise be, but is very close to the bottom of that barrel. Americans haven't come around to acceptance of the European welfare state, and it probably never will if you ask me. Gig workers will be left to their own devices and are the beginning of a new underclass. They're not quite slaves, not quite serfs, and lack the means to improve their lot. Like serfs, though, they will create their own internal rules and morals and institutions, and the business world will adapt around them.