Perhaps nobody has gone over the reasons for a subscription model with you. I can see you're concerned about the monthy fee, so I'll try to shed some light on it for you.
The main reason a company will decide to take this approach is to first recuperate some of the initial cost of the games development. In a perfect world, this wouldn't be the case, but there are benefactors who want their returns and so their hands are tied, so to speak; this game costs a lot to make and the sooner they can make some of that money back, the better.
The second reason is to provide a steady income, in order to pay their customer support teams and cover their server maintenance costs. All massively multiplayer online roleplaying games need to cover these costs, but I'll come back to that in a moment.
The last reason, and for me at least this is the most important, is to provide their players with constant updates, expansions and content. The more money they have at their disposal, the more developers they can keep on the books; thus providing us with more regular content patches.
Now I know what you're thinking; "..but there are loads of games out there that don't charge a monthy fee!" which is true. These are known as Free-to-Play models or F2P. The problem, and I do consider this a problem, with Free-to-Play models is that they still have to recuperate their costs; so what do they do? They find another method; enter Cash Shops and gated content. What are these? They're basically methods where content will be intentionally stripped from the game and hidden behind a pay gate; want some extra bag space? Pay for it. Want to go to that new area? Pay for it. Want to have the best weapons? Pay for them.
Not only that, but F2P games aren't updated on a regular basis; they're actually dying, slowly. It's very rare that a game ever recovers once it has gone Free-to-Play. It's usually deemed as a negative. If you truely love the Elder Scrolls Online, you'll pay the fee and pray others do the same. Help them provide us with the content we want, and don't expect them to give us things for free.