Not much of a prediction.

I haven't seen new 19" arcade monitors for sale in many years. Then the 25" (and 24.8") dropped off. I have a stack of old 19" in vary stages of functioning and made sure that I picked up a tube rejuvenator when I had the chance. If I come across a deal for a nice low-burn tube or monitor, I grab it and put it on the pile.
But ... there comes a point where it just isn't worth the trouble. I recently pulled a flaky WG4900 from my MultiWilliams to work on it. After a bit of troubleshooting, I was at an impasse. Pulled a spare VGA LCD out, wired a VGA plug to the MW board and everything works. It's a little strange looking in the midst of all of the CRTs, but took less than 10 minutes and nobody other than me cares.
As far as the PCBs go ... not such an issue and for more popular options, there are accurate replacements (e.g. jrok's MW board).