"But, is there anyone out there who has a broad exposure to some popular form (film, TV, music, literature, anything) and would argue that the medium is currently in its heyday?"
To be honest I lack the overall knowledge to make a clear cut argument on most mediums. When it comes to Television I think things have gotten worse with the advent of reality TV (which I despise). Reality TV tends to focus on cheap drama, boring arguments, and cliched personalities rather than anything even remotely creative. I hate reality TV.
Literature is such muddied waters, I'd never go near trying to make an argument about that. I do think popular literature has sunk though. Harry Potter is probably the most successful popular literature and it's absolute crap in my opinion.
Music might have progressed since the 90s. But again, it's so subjective and difficult to argue that. Even the presentation of the news in most forms has sunk to an all time low. Newspapers are dying, cable news is a horrific abomination of the truth, etc.
I agree that the popular, most commercial forms of media are not in the least bit entertaining for the most part. My favorite television shows which are character driven dramas with a quirky sense of humor (The Office, Scrubs, Dexter) are dwarfed in ratings by crap like American Idol. But there still is a niche out there for people like me to find what we want. That's the point I was trying to make about niche media.
Even though popular media has gotten more shallow, the art isn't dying, 'cause there's still plenty to be had out there, it's just not the favorite thing for consumption.