The OM-1, however, while being influential (it steered the market into compact machines) wasn't the best implementation of what a "compact SLR" could be. Pentax did this task better, with the MX, ME variants and the LX.
It seems, however, that Olympus had the best marketing department, so people out there believe some outlandish claims about the OM system.
I've never owned one, but back in the day I used a friend's OM-1 for an hour. There were things I really liked ergonomically, like the shutter speed selector around the lens mount and the aperture ring at the front of shorter lenses. It made the camera handle so well. Some folks hated those, but not me. (I disliked the shutter/ASA selector on the Nikkormat, so it wasn't just that it went around the lens mount). The viewfinder was astonishingly large and bright. The low vibration was noticeable. The OM-1 showed what could be done.
Yes, it had its limitations. It had an ordinary center-needle CdS meter, ordinary silk shutter to 1/1000, no shutter or aperture in the finder (but on the other hand that kept it mostly uncluttered).
Olympus certainly spent a lot of money advertising it, and it was very successful. It was never regarded as on the level of the F2, F-1, or XK, but it didn't have the features of those, either. The MX was clearly a competitor when it came to compactness and features, but I've always seen the LX as more a competitor to the F3 and F-1 while being the size of an FM/FE.
I don't really know what the outlandish claims were, but some folks lap up anything.
I knew a guy who said he bought a Minolta because they were the only company which made their own optical glass. I told him that wasn't true, but he showed me an ad wherein Minolta did indeed claim that. So I showed him Nikon and Fuji brochures I had in which they showed them making glass (and the exotic platinum crucibles they used to do it). Canon claimed to make their optical glass, and were promoting their big foray into fluorite elements. And there was some other maker I can't remember. Konica, maybe.
I think it's likely that they all bought glass as well, as that would make economic sense with readily available, more ordinary types. Two very highly regarded lens makers I can think of offhand never claimed, to my knowledge, to make their own glass: Pentax and Leica. So making optical glass is not a prerequisite to making excellent lenses. But claiming to be the only one to make your own glass sold some cameras to easily impressed people.
BTW, the guy was crestfallen and a little upset once he found out the indisputable truth about Minolta's claim. I told him don't worry about it, his lenses weren't any less excellent because the claim was false.