And, well, most of the Coalitions were almost exclusively funded by generous British subsidies. To Austria, Prussia, Sweden, Russia, and a couple dozen of minor powers. Industry made Britain able to afford that.

"In terms of soldiers the French numerical advantage was offset by British subsidies that paid for a large proportion of the Austrian and Russian soldiers, peaking at about 450,000 in 1813."

[0] https://en.m.wikipedia.org/wiki/United_Kingdom_in_the_Napole...