Corporate politics and errant management edicts kill companies as well. Leaning too hard in one direction usually tips the boat. What kind of fantastic business decisions have been taking place recently?
Perhaps the 20-40-year-olds know a little more about the good business than you are giving them credit for. I see thrashing about, sudden shifts in direction, weak communication, etc. That is not the sign of a health; it is a sign of trouble.
If I believed every passionate fans who are telling me something is dying then there would literally be zero products left.
The doom and gloom hearing here is the same we heard when Gamma World came out (They're going to cancel D&D!)
Or when Essentials came out (Welcome to 4.5, 4e lovers hah hah hah!)
Or when Dark Sun came out (Hope you enjoy them utterly ruining the old school setting!)
Or when Eberron setting came out (Remember Forgotten Realms, that's what your precious setting is going to become!)
Or when 4e came out (I give it a few months, tops!)
Maybe if someone who genuinely cared about the game and genuinely loved 4e and genuinely knew the ins and outs of the industry and they said there was a good reason to be very worried, I'd take it in stride. But that's not happening.
What is happening is that a lot of people that have been preaching the death of D&D for years, people who have done nothing but attack and insult WotC and 4e since the day it came out, are crowing on how they were apparently right "all along."
Edit: And wishing things would go back to the days of TSR is the very definition of nostalgia goggles. Boy 2e sure was fun, what with D&D literally choking itself to death and the company suing their own fans into oblivion.