Why no more Pretorias?

Those really cool eyepieces from the early to mid '80s with built in paracors from UO were only a brief fad that soon died after the advent of the paracor. My question here is why? It was a great idea at the time that there be these coma corrected eyepieces that show no significant coma with a fast newt. I would like to see them come back.

The 20mm Pretoria is my favorite. Much more compact
than coma corrector + eyepiece. I think ultimately
the moderate field-of-view (60 degrees or so) may not
have competed well with other premium eyepieces
(Naglers and Ultra-Wides around 84 degrees).

I would like to see a 1.25" threaded coma corrector that
can be placed on an eyepiece much like a filter. Maybe
if you had eyepieces with different focal points, you'd
need to add some spacer rings. But it seems doable.

I think it is simple economics. A paracorr costs about $300 new. Some of that is barrel, cell, etc., so there would be some savings by incorporating it into an eyepiece, lets say it would add $100 to cost of an existing eyepiece to make it coma correcting as well. Lets say an average scope owner uses 5 eyepieces. That means getting 5 coma correcting eyepieces will cost an extra $500, vs. an extra $300 for the paracorr plus 5 normal eyepieces. If you want more eyepieces, it gets worse. If you have a second scope that doesn't have coma (say a small refractor to complement your large dob), now you need a complete second set of eyepieces for that scope.

What I would like to see (and it may becoming soon) is a focuser with a built-in paracorr for large dobs. That would save some weight, money, and fiddling in the dark.

Jarad