What 'other things being equal'?
The Contax lens mount was a bad joke -- far too small a throat, doubled-up inner and outer bayonets, absurdly over-complicated focusing mechanism-- and the shutter was pretty nearly as bad; Canon never switched to a faster bayonet mount with auto frame selection; Nikon was mostly a somewhat improved Contax, still with a good deal of bizarre 1930s ergonomics; and the Kiev was basically a Contax, later minimally updated.
The Prominent was grievously limited by a behind-the-lens shutter, and the Retina series by relying on interchangeable front groups rather than interchangeable lenses. Most of the others appeared in tiny numbers -- the Hensoldt Reporter was one of my favourites -- with limited lens choice, sometimes of mediocre lenses (e.g.Paxette).
There was of course the Alpa 7 which was both a reflex and a rangefinder, and had a modest choice of excellent lenses (with the option, via adaptors, or many more) but they were staggeringly rare and made Leicas look inexpensive.
In other words, we're left pretty much with fixed-lens RFs (in fact, ONLY with fixed-lens RFs by the later 1960s) so it's a bit apples-and-oranges already, and frankly, most fixed-lens RFs were built down to a price. A few were truly excellent -- Konica springs to mind -- but the Retina's glory days were over (treating it as effectively a fixed-lens camera) and (for example) Yashica Lynxes were really only on the good side of mediocre.
I came to RFs at the end of the 60s (when some Retinas and Prominents were still in professional use because of leaf shutter flash synch) and in those days no-one made the sort of overblown claims that are made today on behalf of quite a wide range of mostly obviously inferior cameras.
The Leica was generally recognized as the pinnacle, and the main reason not to buy one (then as now) was because you couldn't afford one or, if that formula didn't appeal to you, because you couldn't 'justify' one -- though it's hard to see, sometimes, how 'afford' and 'justify' are differentiated, because we have to 'justify' only what we can't really afford. As soon as I could afford an M, I decided I could 'justify' it. 'Can't justify' means either 'can't afford to buy it on a whim' or 'don't want it badly enough to pay what it costs'.
Results? Can I tell my Leica shots from Retina shots, Prominent shots, even Nikon F shots? Occasionally, but even then, I'm not sure whether I'm remembering which camera I used, rather than seeing the difference. But what does it matter? I'm still using the Leicas, and so are quite a lot of other people, whereas most of the rest have plummeted in value unless they are very rare and interesting (Ektra, Foton -- I know, not 1960s/70s). There may be a reason for this, and it ain't just snobbery. Yes, Leicas were and are better.
Cheers,
R.