In the US North, around the time of independence is when slavery there was banned.
In both places the "IR" started not long afterwards, with the UK starting first.
Probably because labor was not cheap anymore, people had to find a new way of production.
The Slavery Abolition Act of 1833 formally freed 800,000 Africans who were then the legal property of Britain’s slave owners. What is less well known is that the same act contained a provision for the financial compensation of the owners of those slaves, by the British taxpayer, for the loss of their “property”. The compensation commission was the government body established to evaluate the claims of the slave owners and administer the distribution of the £20m the government had set aside to pay them off. That sum represented 40% of the total government expenditure for 1834. It is the modern equivalent of between £16bn and £17bn.
The compensation of Britain’s 46,000 slave owners was the largest bailout in British history until the bailout of the banks in 2009. Not only did the slaves receive nothing, under another clause of the act they were compelled to provide 45 hours of unpaid labour each week for their former masters, for a further four years after their supposed liberation. In effect, the enslaved paid part of the bill for their own manumission.