It's not that S&W "cannot", it's that S&W has elected not to make them anymore. It isn't about what other gunmakers are doing, it is about what S&W has decided they wish to do.

It truly is no more complicated or mysterious than that.

Building the 3rd Gen takes some off-site suppliers and vendors, S&W doesn't carve every single piece from a chunk of metal. It also takes floor space for the tooling that has since been reappropriated for othet work. It takes a staff of employees trained on those particular pistols.

S&W has decided that those reasons and the costs associated with them don't add up to potential sales of new production older technology.