"is it still valid in todays climate?"
In my opinion, yes. Hopefully, from time to time,it will be on the the schools syllabus as required reading and it will remind the present younger generation of that insidious and oppressive power, where money and social position allowed the subjugation of working people, and which could easily raise it's head again and take our society back to a nation of those with plenty and those with nothing,and make a mockery of those sacrifices, so bravely made, by "ordinary" people who laid the foundations of our still very imperfect, but much fairer, society. And,after reading Robert Tressell's (Noonan?) masterpiece, one or two of the social tracts by G B Shaw would also bring home how much society has changed through the efforts of people motivated by humanity instead of monetary gain.