This article relates to the fine art market. I'm sure the great majority of fine art buyers are not investing in comic art.
Personally, I prefer comic art, but the two worlds are still very much apart.
What will happen in the future is anyone's guess.
Personally, with my limited experience in and around the fine art market, I see a very large contingent of "those people" never deigning to recognize comic art on the same level as the art in their world. I'm guessing their world will remain mostly separate from ours.
I foresee a separate "comic art market" coming to fruition at a different level. A different level of price as well as interest. This market may capture the imagination of a different contingent of people, so while they are not now fine art buyers, they may become comic art buyers.
Your milage may vary...