MIM parts came into common use decades before S&W got in on the act. Dan Wesson was one of the first companies maligned for using such parts (I once owned both the .357 and .44 models), and IIRC, I once owned a Colt Trooper III that had the trigger broken at the hinge and I heard all about how crappy Colt revolvers had become from the gun smith I had to order a new part from.
As with all things, the technology has advanced since Germany first introduced "sintered metal" bullets with the 9mm in 1908. Today it's hard to find any mechanical device that doesn't use MIM or some form of compressed metal technology. I own quite a number of expensive knives that use advanced "powdered steel" alloys such as Elmax and M390 in their blades and those knifes are tough, and hold an edge. Microtech is renowned for the sheer abuse their OTF knifes can withstand without even being damaged, let alone "broken" - using some form of compressed metal steel.
The ONLY reason to even be talking about MIM parts is because gun makers are still slavishly devoted to making revolvers look "classic" - even 1911's and such. GLOCK showed the world how it CAN be done using stamped, tempered steel parts for EVERYTHING but the locking block, barrel, and slide, but the consumer expects them to look "industrial" whereas they expect a S&W New Classic to look pretty much like an "Old Classic" which is why they COST SO MUCH!
Even my new Colt Python has powdered metal parts and so much the better for it. Such parts drop from the "mold" perfectly dimensioned with no stress points caused by high-temp forging followed by machining. Compressed steel alloy parts form extremely uniform grain structures and reduce what were once labor intensive, "fitted parts" to "drop in" as long as the CAD engineers did their part!
People not familiar with machine work lack an understanding of just what "precision" means when it comes to making metal parts. While a hand machinist with the knowledge and skill can create one-off parts to an amazing precision, it's time consuming and expensive, and becomes corrupted when such parts are fitted into a "system of parts" with less than perfect precision. The very BEST a human eye can perceive is about 0.001" whereas a CAD program can locate the center of a line to the precision of the screen that displays it, and to the precision of the CAM controlled mill that machines it! "Casting, injecting, or compressing" super steel alloys results in parts to 0.0001" precision - 2.54 microns.
Rather and "diss" our domestic gun makers for trying to give us a "classic experience" with ever better alloys and methods of manufacture, we should be cheering them on! Whenever I hear someone pontificate: "They don't build them like they used too!" I'm proud that this is so, but also somewhat disheartened that those who make such proclamations have absolutely ZERO understanding and regard for the man hours it took to "build 'em like they used too," while still ending up with guns that were "no-two-alike" due to the need for so much post-manufacture hand fitting.