But not many. The great thing about fd lenses is that nobody wants them so they are very cheap (with a few notable exceptions like the tilt/shift lens, the 85 1.2,etc) but have good quality. My grandfather still uses his ae-1, I dont think there are many left like him, so this just leaves a bunch of nerds. The benefit of mirrorless is the short flange, if they manage to make the sensor pack and screen thin enough they would obviously go for the ef mount instead of fd and forget about ef-m (is there any notable lens for that mount?). Nikon is going to do this with the f mount if the rumors are true. A great move if we have a look at the sony lenses which are just as big as long flange distance lenses, or even worse if we go into longer focal lengths.