I also refuse to pay monthly subscriptions for any game.
I hear you, and mostly agree.
There is, however, one thing where I think a subscription model would be good: squadrons and factions (and possibly upcoming features such as carriers). The insistence on in-game tools is seriously limiting what can or cannot be done. If a player group subscription would support making "meta game tools" for the web, complete with nice APIs (allowing for example a player group to code their own Discord or forum integration), along with fleshing out the squadron/faction game play, I would be totally for it.