I assume it has to do with a wider company perspective for KAI which sees Kershaw as a feeder brand for ZT. So, if cheaper artsy/fartsy Kershaws sell, then they make more expensive arsty/fartsy ZTs to sell to those buyers who want to move up.
But, there actually are still more "old school" style ZTs being sold -- like the 0308, 0350, 0357, 0393, 0450, 0452, 0462 0470, 0562 & 0770 -- than the newer arsty/farsty designs -- like the 0022, 0223, 0230 0235, 0707, 0762, 0990.
So, the perception that ZT isn't living up to its tradition isn't entirely accurate.
It's just that the few newer "old school" type designs that they've produced -- like the 0308 & 0357 -- really aren't all that exciting to fans of the older designs and all that remains are older models that everyone who is/was interested in has/or has passed on already.
However, most of the newer and older ZTs that they are selling are smaller/lighter knives which gives also the impression that ZT has given up on building larger/heftier knives built in the "over built" tradition -- like the 0200, 0300, 0301, 0400, 0550, 0551, 0560, 0561, 0804, 0850, 0909 & 0920.
The only recent exception to the small/lighter trend in ZT knives is the 0308 that I never bought because it isn't that much different or better than the 0300s that I've already got. Not sure how well the 0308 has been selling but, if it a knife doesn't sell, ZT is pretty quick to pull the plug on it.
Anyway, if KAI is doing well selling the smaller/lighter and artsy/fartsy knives, can you really expect them to make more "overbuilt" knives? I think not.
Things change (all the time). Often in ways we don't like. Really nothing be can do about it, except whine, but whining won't change anything.