Has the meaning of amateur changed?

David Brooks writes in the New York Times:
Over the decades, the word amateur changed its meaning. It used to convey a moral sensibility, but now it conveys an economic one: not getting paid.
Source: 'The Amateur  Ideal'

Brooks is referring to university sport in the USA but has their been a more general change? Is amateur now used largely in a pejorative way - as in 'amateur hour'?