How can they be a subscription? There's no requirement to buy cosmetics from the store and access to the game is not stopped if we don't buy cosmetics....
Why do you feel the need to apply arbitrary descriptors?
Do yourself a favor and go google some articles on the controversy that's been surrounding microtransactions on high profile games over the last year. What you think a subscription is, and what the gaming industry thinks a subscription is, are two entirely different things and their definition is very broad and open to interpretation.
None of it is directly relevant, but it will give you some insight on just how different a financial expert's description of voluntary is compared to yours.
Why should they limit their sources of income to silly boundaries set by a dictionary description? Webster didn't write the guide to financial success. They can't even afford to print physical copies anymore.
Access is stopped if you stop buying cosmetics, just not immediately. When ED becomes unprofitable the servers will shut down. No ambiguity about that. It's an online game and online games cost money. FDev is not obligated to go in the red for you.
The median age on this forum is really starting to bite it's own tail in it's ignorance on just how the gaming industry works.