But accelerating the decline of your profitable niche by withdrawing from the niches that fed the creation of your current niche, is probably not good long term thinking.
In the case of comics, Marvel and DC has a market of 30's males now because they served the market of kids in the 80's and before.
If they want to retain that profitable niche, they better make sure they develop interest amongst younger readers.
Is it declining? It would seem to be growing, but mainly amongst a certain demographic (who happen to have a lot of disposable income).
As mentioned elsewhere in the thread, comics are no longer a mainstream entertainment medium compared to movies and videogames, so comic franchises are branching out into these areas.
In the case of comics, Marvel and DC has a market of 30's males now because they served the market of kids in the 80's and before.
If they want to retain that profitable niche, they better make sure they develop interest amongst younger readers.