And the disadvantages of that sort of thing:
- A lot of people don't care to do subscription games.
- A lot of people will simply not pay the subscription and drop the game. They're used to playing it for free, paying for cosmetic additions only. That's the way the like it. That's the only way they'll play it.
- If this was designed to be EVE but with a full 1:1 galaxy on steroids and everyone expected to pay a monthly fee at least people would have been able to decide to buy it or not. It's not a good idea to change horses in mid-stream.
4. Subscription based game would be really difficult to recover from disasters like Odyssey launch. Players had already payed for the Odessey DLC so to revisit the game every couple months wasn't a big deal. But players aren't going to pay a monthly fee just to see if the game is fixed. Easy to say "don't launch a game breaking DLC"... but it happened. And if it happens again (which it might... because the last one was "unexpected")... it would be game over.