It would make sense if the amp market declined over time. It would seem more of a steady decline, though, not a sudden burst of any bubble. Rock/hard rock/metal seems to be declining in popularity, especially with the younger generation, so the amp buying market is aging and reducing. And for the younger generation, mired in student debt and with home ownership rates falling, digital is a no-brainer at apartment volumes compared to a 50+ watt tube amp. You're picking between endless choices of really good sounds, compared to maybe 1-4 sounds that would be awesome except they're completely unusable for your situation. And, for gigging, it may feel awesome for the player to have a bunch of air moving behind your pant legs, but the audience doesn't give a shit. They mainly care if they can hear everything, and the best way to do that is with low stage volume and having the PA do the heavy lifting. Even Meshuggah, when they got their totally awesome tailor-made boutique tube amps, used them direct through Torpedo Lives.
But, trends can be cyclical, so who knows what will happen in the future with popularity of rock music and/or big tube amps.