Subs models didn't kill SWTOR btw.
What killed swtor was
1) Game was too easy
2) No open world PvP that works
3) Game breaking bugs in end-game instances
4) Only "end-game" was to replay alts
5) Game was entirely content related, and they couldn't make content fast enough, or with enough quality.
6) Crap servers - couldn't get enough people on one server initially, had to expand number of servers, then had to drop servers, merging everywhere.
7) limited number of PvP arenas
8) very slow respose to legitimate complaints
People were happy to pay, but not when there was no game to play. E: D shouldn't have that problem. Firstly it's no where near the hype levels of SWTOR. Secondly, it's a sand box, so it will always give entertainment to a hardcore group of fans.
It's certainly worth going through SWTOR at least once now that it's F2P, and I hear they have also added new stuff to appease the more demanding gamers. Shame they launched too early and couldn't keep up with them in the first place.
Anyways, Elite: Dangerous needs to make money for Frontier Developments. Think of the staff costs in that team. They all need to put bread on the table. And their shareholders want to see the fortune of the company improve. So yeah, if we have the following options
Option 1) Buy game - play game. Free, forever
Option 2) Buy game + expansions. Play shiny new stuff each time it's release
Option 3) Buy game + CashShop/MT. Suit yourself how much you buy, what you buy and when. Some perks, costmetic items, cash
Option 4) Buy game + payupfront subscription type thing and get some perks, equivalent credit or whatever the deal is.
Four options, covering all potential customers. I'm sure with time, effort, concentration and a nice packet of post-it notes, a decent plan could be drawn from teh above.