It started before that. The powers that be in western European countries can no longer deliver prosperity or security to their citizens, so must instead use force and repression to cling on to power.
Many European countries got rich without colonization (e.g the Baltic States before WW2, or Austria-Hungary).
Moreover, economic studies show that the profitability was discutable - in the case of France it was a net loss due to the massive infrastructure costs and the subsidies for non-competitive industries.
In 1096AD, while the Mayans were plunging daggers into their sacrifices' chests, England was busy opening Oxford University. What sort of fool would think that somehow all the engineering and scientific advance that would allow England to reach around the world and establish an empire could possibly have been caused by that empire?
