JC:
Those wet clutches in tractors (and in motorcycles) are amazingly
robust and long-lasting. Electrically-actuated (not hydraulically-
actuated) wet clutches have been around a while (e.g. the Kubota
GST), but they usually include a dry clutch, too. My JDs had no
clutch at all for the main drive train and electrically-actuated
clutch for the PTO. Eliminating the foot clutch entirely has some
real advantages, but I think that your main point is easier clutch
replacement. Dry clutches are still seen as wear items that need
periodic replacement. This is despite the fact that the super-low
gearing of a tractor should require very little clutch slipping to get
the machine going. Many dry clutches last for decades and 1000s
of hours on tractors, properly used. That said, I think that any sort
of wet clutch (foot-operated or electrically-operated) should very
likely relegate the tractor's clutch to a very rarely replaced item.
Tractor splitting should become extremely rare. I wonder why we
don't see more foot-operated wet clutches on CUTs.
BTW, my recently sold M/C had over 50,000 miles on it over the 27
years since I bought it new, and the clutch never exhibited any signs
of needing replacement. Driven mostly in town, slipping the clutch
to get started was ususally how it was used.