After every revolution, there is a conservative counter-revolution...
Williams was making 3-rail O gauge throughout the '80s, although it took until '87 or so for quality and robustness to approach the better Lionel stuff. Williams stepped out around 1990, and Weaver took over the relationship with Samhongsa. With help from small players like Right-of-Way and 3rd Rail, by 1992 there was a decent variety of 3-rail brass. As far as I know, Mike Wolf was a retailer, and had little to do with making or importing these locos.
MTH began selling O gauge under their own label in '93. Although many items were scale-proportioned, the engineering design was toy-like, and in some ways a step backwards from what Williams, Weaver, and 3rd Rail had been doing. Gear ratios were straight out of the Fisher Price aisle, and early Premier steam didn't coast well at all. Their diesels lacked the realistic fixed pilots or single-digit scale speeds of the Weaver Ultra Line or Red Caboose GP9. So yes there was a contribution, but also a lost opportunity. After several years, HO, G scale, and even S-gauge still had better-engineered, more realistic, more affordable mass-produced models. Instead of continuing the "revolution of realism" begun by Weaver and even Atlas with its excellent SW switcher, MTH opted to design for producibility, not necessarily realism or ultimate performance. These were more affordable but still high-priced, and operationally, still very much toy trains.
Circa 2011, MTH turned away from North American 'O', and shifted its product development focus to HO scale. What's ironic is that their HO steam locos were "made right" from day one, embracing best accepted engineering practices. Split chassis with a "bottom plate," replaceable wheels and axles, an optional non-rubber-tired wheelset in the box, etc. They obviously had the know-how. Yet in fifteen years, they never saw fit to retool and incorporate these improvements into their O scale product lineup.
This post may be perceived as critical. I don't hate MTH, and I'm not partial to any one brand. But as someone who lived through this era and spent some of my first paychecks on early MTH products, I'm trying to bring some objectivity to this thread. My mind is open, but my wallet generally isn't, until someone builds a "better mousetrap." I'm impressed by quality engineering and built-in performance, not failure-prone gimmicks or tack-on features. Big, quality motors. Low gear ratios--30:1 or bust! Big flywheels or back-drivable gears with plenty of coasting. Everything easily replaceable, customizable, and upgradeable. Parts-is-parts: put an exploded diagram on the web, and sell me as many as I want! Run 'em till the dies fold, none of that "limited production" collector B.S.
The opportunity is still there... The ultimate O gauge trains haven't been produced yet! Google some parts diagrams for the American Models 4-6-2, or look under the hood of one of their S-gauge diesels. Heck, look at a US Hobbies 2-rail loco from the 1960s. First one that builds a semi-scale loco like this gets my money! So which one of you is the next Mike Wolf!?