...they've updated or newly released every L prime at 100mm and shorter in the past 4 years (including TS-E models), except the 35L.
The TS-E 45mm & TS-E 90mm were not, nor was the MP-E 65mm. AFAIK, the MP-E 65mm is an excellent lens without any competition, so I would think it's low on Canon's list of lenses to upgrade.
The TS-E 45mm, TS-E 90mm, and MP-E 65mm were/are not L
primes. The following are the current L primes at 100mm and under:
EF 14mm f/2.8L, updated to MkII in 2007
TS-E 17mm f/4L, released in 2009
TS-E 24mm f/3.5L, updated to MkII in 2009
EF 24mm f/1.4L, updated to MkII in 2008
(EF 35mm f/1.4L, released in 1998
EF 50mm f/1.2L, released in 2007
EF 85mm f/1.2L, updated to MkII in 2006
EF 100mm f/2.8L Macro IS, released in 2009
All of them except the 35L were either newly released or updated in the last 4 years.
To each his own, but I prefer Canon came out with a few non-L lenses. A 150-450mm f/4-5.6 for ~$1,000 would be nice. A new 135mm f/2.8 which is optically as good as the 85mm f/1.8 would be nice, if the price tag would have a reasonable increase of ~30%.
What, you don't like Soft Focus?
Seriously, the EF 85mm f/1.8 is an excellent lens, great value for the optical quality it delivers! If Canon were to update non-L EF lenses to the same standard without driving the prices through the roof, that would be great (and might weaken my resolve to stick with L lenses for future purchases!).