In Huxley's day, that was more true[1] than it is today. Look at someone like Lord Kelvin, for instance. State-sponsored science wasn't really a thing yet; most of it was done by people who had the time and money to pursue it.
[1] That is, it was true of scientific progress. As you say, social progress often involved finding a way to destroy the aristocracy's stranglehold on money and power.
Baron Kelvin of Largs became that because of his work, not the other way round.
His father was a University Professor.
Having said that, in the history of science there's a surprising number of people who got to focus on their hobby due to family wealth, and access to all the best toys allowed them to claim a lot of firsts.
[1] That is, it was true of scientific progress. As you say, social progress often involved finding a way to destroy the aristocracy's stranglehold on money and power.