I sigh when I see others scream over 'getting what they paid for'.
Software is a virtual item. You pay for a license. A right to use, and/or access features when conditions allow. MMO's introduce an interesting twist to this since it is a virtual world with items, currency, and characters. You do not own any virtual items. The company that made them does. Your license allows you the right to use them, but does not give you ownership. Read the EULA and TOS if you do not believe me.
Everyone is getting exactly what they paid for..... access to virtual things when conditions allow.
Now I will say that most software companies will tend to do the right thing and try to keep customers happy. In theory they do not have to, but no one would pay them if they did not enjoy the product. The rather common practice for software with the access to the internet these days is to release software as a open frame work. Once people start buying the company listens to feedback and designs features based on the feedback. This saves time, money, and overall production. Compared to earlier years it does seem like software is unfinished, but development wise it allows companies and customers to both get more of what they want. Sure companies could take longer to develop software, but that increases costs. The company would have to delay releases, increase the purchase price, and might never release the software as components become obsolete. Things are done certain ways for certain reasons. It may not seem right all the time, but that is the way of things.
So if you feel that you have been cheated, that you did not get what you paid for, and want to blame someone I suggest you look in the mirror first. You choose to hand over your hard earned money for that cardboard box, and shiny disc. You bought a license, and you agreed to the terms of the EULA/TOS. Consumers sometimes forget that like themselves, companies, are protected by the law also. You agreed to acontract, and it only promised you access to a server when conditions allow. Most MMO EULA and TOS state that you are licensed to access a server when conditions allow. That is what your $15 a month grants you, and nothing more. Another thought to consider is that the company and shut down the server when ever they want, even permanently, and that is it. They would not owe you anything.