Not sure about his forum presence, but I dropped an upper off with him last week, so he's still in business. He can't mill slides, FYI, but knows someone who can. Most local shops outsource these types of service to places like Parker Mountain Machine.
If most local shops are outsourcing this work, it must be due to a lack of space for a good sized vertical mill, because any gunsmith who has the mill would be able to machine the slide. It's not difficult. Setting up the slide in the mill CAREFULLY without a dedicated fixture takes 30 minutes or so, then another 15 to do the milling.
With a dedicated fixture (bought or shop made) maybe 10 minutes to set up and 15 to carefully mills and clean up the edges when the milling is done.
In the old days, a gun shop that had a gunsmith but no lathe or mill was called a sporting goods shop, the gunsmith did simple repairs, fitted parts, but couldn't drill and tap a receiver for scope mounts (well, he might if he had a really big, heavy , solid drill press with a X-Y cross feed table bolted to the drill press table).
The gun shops always had a gunsmith with a lathe, and mill, and way back, maybe a shaper too, and a surface grinder as well as a drill press, belt and wheel grinders, etc.
The gunsmith would be a fairly accomplished machinist usually, often a retired machinist or tool and die maker turned gunsmith in his later years and in those cases, an extremely accomplished machinist who could thread barrel blanks, and chamber them, often without a chambering reamer, it can be done with just a boring bar, have done many that way myself in years gone by for oddball calibers where there just wasn't enough demand to justify buying a reamer, or making one, have done that too, made the reamer from scratch.
But those skills are dying off today it seems, sad state of affairs.
And rents are so high on shop space these days a true gunsmith can't afford the square footage to have a lathe and mill on the premises, so that work gets sent out. Sales Volume equals money for shop space it seems.