>What's the difference? From what I can see, TV series are just as heavily pirated as music is.

The difference is those series have still enough paid subscribers to make the production costs and handsome profits worth it.

But producing music these days is extremely cheap, it's not like decades ago where it required time in a million dollar studio to produce something that sounded decent. Meanwhile TV the opposite is true, budgets have soared with the increasing use of spectacular sets, CGI and special effects.