I wonder if the standards modellers expect nowadays is part of the problem? Around 20 years ago I made exclusively 1:72 aircraft, WW1 and inter-war. I used the trusty Revell, Airfix and Matchbox offerings, plus a whole range of limited run kits, either injection (such as Merlin and Pegasus) or vacform (Contrail). I don't think think there's such a wide range of subjects now. I get the impression that the really small limited-run companies are no longer around, possibly because the kits required a lot of effort, and the end result was rarely as good as you'd get today. There are smaller companies out there, but their niche products add photo-etch and resin to the injection moulded parts and cost a lot more. Most of us (like myself) look for lots of interior detail and finely etched panel lines, whereas before, I was satisfied with scratch-building a seat, straps, joystick (plastic rod with a blob of glue) and instument panel (plastic card painted black with a few dials scratched on with a pin), and maybe sanding down the trailing edges a bit.
I suppose I'm lucky - having come back to the hobby recently, with WW2 1:72 aircraft as my chosen area, I'm revelling (no pun intended) in the quality of the kits, and I'll probably be dead before I run out of kits to build. If I'd been modelling continuously all these years, I'd probably feel things were getting stagnant and looking to scratchbuild or kit bash new subjects.