Since Ruger now owns Marlin, I would love to see them make sort of a Super Model 60, in .357 Mag.
While it is a neat idea, I don't see it happening, there's just too much stacked up against it being profitable.
First off, it could only resemble a Model 60 on the outside. The entire gun would have to be designed from scratch, and that's not cheap.
Next point is caliber, and gas operation. Simply put, lead bullet ammo does not "play nice" in gas operated firearms. Ruger went through that with their .44 Mag semi auto decades ago.
Despite numerous and frequent advice/warnings to NOT shoot lead bullets in that gun, people did it, anyway. The had trouble, gunked up the gun, and then, of course, BLAMED RUGER....
Since even today the majority of .357 and .38 Special ammo has lead bullets, its going to happen. And expect the same thing, ignorant people will loudly, publicly, and frequently blame Ruger, and the gun's design, and the gun will get a poor reputation and sales will drop, Not fair, not HONEST, but it's what people WILL do.
Next point is relatively minor, but Ruger does not have a great track record with tubular magazines. This was another point of complaint about their .44 carbine, and again, for nearly the same reasons. People shoving lead (and soft lead) ammo into it, gunking things up, and it was very difficult to take down and clean. LIkewise, there is the built in difficulty of unloading the tube. The Ruger rotary box magazine is superb, and its almost a given Ruger would use that over a tube magazine system these days.
Lastly, there is the radical political climate today that seeks to ban/or otherwise restrict semi autos. ALL of them. Even ones with fixed magazines.
The idea might go somewhere as a pump, but as a semi auto, I don't think so, not these days....sadly...