I don't understand why they don't release to subscribers first then bang it on Steam say 6 months later. Even with piracy that would surely be increasing their revenue. People who are desperate to play pay for it on subscription and LoP maybe get to keep some folk subscribed, then they get a second wind of revenue when the game is released on Steam. A lot of people who use Steam won't even think to look for sites like this if it's cheap enough on Steam. Say £5 for the main release and £2.50 for each update/DLC.
From following their blog though it seems the devs at Lop can be quite petty (with feedback etc) so it wouldn't surprise me if they're not launching games on Steam just to spite pirates, even if it reduces their eventual cashflow.