Interesting question but for me no. One appeal for me in the MMO is the persistency - its one of the major appeals. I am one of those people who would like to port my Warden from one sequel of DA to another
or through out the NWN, Fallout, etc. games.
Although I understand the point they seldom end. But I have a fairly vivid imagination and I pretty much make my own game within the MMO game world. I sometimes wonder if the current generation of gamers (console), who grew up with more advanced games, sometimes prefer the more cinematic style games with action because they are used to games filling in all the parts. Seems like sandbox games (which MMO are in many ways) are for those who don't mind filling in things in their own head .. but thats another subject I suppose
So for me I like knowing I can logon at any point and continue my character. Not indefinitely ... I lack the stamina for that. But a really good MMO can hold me for years. Most SRPG games will only hold me for 3-6 months on average, unless really, really good. Expansions also help (but DLC not so much as they are to short).
I don't play MMO like most folks (or maybe I do and don't know it) though. I am very casual, I hate raiding with a passion, and I hate powergaming. That doesn't work in well with most groups. I do like chatting with folks and some light RP so I tend to join social guilds where I can chat, do some fun guild stuff, and avoid the stress and hassle of raids and competition.
The more time I invest in a character the less happy I would be to see him go. So it is the persistent nature of an MMO, combined with all the dynamic content and changes that are made, that make it appealing to me.
In an SRPG I don't mind it ending although I prefer a nebulous ending to my character. In DAO, for example, I never took the option to kill my character - although if I knew the "out" was evil I would have - sometimes RP trumps my desire to let my character live. But it was vague enough I was okay with it.
I never see all the content in an MMO (since I don't raid and dislike grouping) and seldom see it in a SRPG either as I seldom play all sides - I dislike being evil and always play male. So I am no stranger to missed content. But I also don't want my character being killed every week - that would suck. I would have no connection to the game or any desire to play. My character is me in the game and what I enjoy playing. All things end but if it is to quick it becomes pointless IMO.