M. du-b
It would have been nice if 30+ years ago when I started buying "G" gauge (scale back then) if there were well defined scales on the market, like there are today. But there weren't, LGB was the only mass marketed trains available for 45mm gauge track.
Now we have 1:20.3, 1:22.5/24, 1:29 and 1:32. At the time LGB was listed as 1:22.5 (correct for meter gauge). They then started making trains other than European meter gauge, notably, American narrow gauge. They lettered some of their narrow gauge cars for American standard gauge railroads, Santa Fe, Union Pacific, Southern Pacific , and many others. A little later they started making longer more modern North American freight cars, based on the 40' car length. A little later AristoCraft and USAT made similar sized cars and engines to be compatible with the "modern" LGB cars. These scaled out to about 1:29. I think, but don't know for sure that this was all long before MTH entered the "G" market. I for one had a relatively, large collection of 1:22.5/24and 1:29 rolling stock. Since I had this on hand, I did not see any reason to start a new scale, 1:32, just to be correct.
Had I been a recent entrant to large scale, I might have gone to 1:20.3 and 1:32, but we will never know.
I imagine that many others in the hobby got into 1:29 in a similar way. There was nothing else available for those interested in standard gauge large scale, and we liked it, correct or not.
Chuck