Your first claim needs a lot of work. Works that attain the pinnacle of artistic merit are usually ahead of their time, and are not aimed at pleasing the majority. How can the majority know they want something what hasn't been created yet? Historically, this has often been the case in literature, movies, and modern art. Take the movie Avatar, for example. It was aimed at a huge audience to make tons of money, and it did just that. It is a significant artistic achievement as a movie? Gods no. It will be forgotten in a while.
I can't tell Skyrim won't be an artistic achievement, but it is my prediction that it won't be as great an artistic achievement that it could be. It won't be timeless.
No, my claim doesn't need a lot of work. Picasso's work was very popular during his lifetime (he was very rich before he died), Sergio Leone's movies were very popular when they were released (at least where I live), Donne's sermons were very popular when he pronounced them... all of these are the very definition of art to me, maybe your definition is different. Yes, some people's works were not popular when they were first made, but that's not true for everything artistic that was made.
I don't consider Avatar artistic in the slightest. It was merely entertaining, and a technological demo.
A prediction. So what are you basing your prediction on? I'm just asking because I'm curious.
edit:
Those work of arts are very popular because they are good, they aren't good because they are so popular.
Skyrim WILL be a (lot) worse than it could have been because it is aiming at the majority/a broader audience, while it COULD have had a broader audience by being very good.
Because off all these works of art you refer too, how many have been made based mainly on the idea of reaching a audience as big as possible?
No, I disagree, again something can be an artistic achievement regardless of the aim of its creators. Many paintings from the Renaissance were made merely to please their buyers (flattering portraits, religious scenes commissioned by the church...), and another example I used above: John Donne's sermons were obviously made to please his public.