Here is the problem , when someone states that a scope can take XYZ power that is ones opinion if the image is good. No disrespect to anyone but that is not a valid indication of optical quality, it is a personnel judgment. Also there can be a simple reasons as to why an image degrades at high power so the optics might be fine. I can't count how many eyepieces I have found that at one point were disassembled and put back together wrong. Again they still form an image just one that as a good as it could be. I have seen objectives that were backwards in the cell for years and people of said the image was great ! It took me a few minutes to find the problem and another few to fix it. The result was a telescope that now gave an image that it should have. I can't stress enough it is not difficult to test optics. Many tests like checking the proper alignment of the air space just requires placing the lens under a common CFL bulb and observing the pattern of the interference fringes. Correctly done star testing and/or bench testing removes the bias and you get the real quality of the optics.
The other thing that many don't appreciate is how variable figuring optics actually is. It is not like machining parts were one can make millions of them to tight tolerance. Glass and pitch act differently all the time. Go up into the ATM Forum and see the issue people have in figuring optics. Modern day technique can get SOME optical designs to 1/2 to 1/4 wave almost all the time without any need to test but others require testing, correcting, testing etc to get them to at least 1/4 wave if not better. That is using modern techniques but we are talking about optics made 60 years ago so the variability can be much greater.
Variability when people push glass in their basement by hand, or use crude grinding machines, primitive manual spherometers, techniques culled from ancient texts to make telescopes. But machines make most of the average optics today do it start to finish with no human hand contact and with reasonable and consistent results. The problem in those days was that they only had "X" amount of time to produce a lens and maintain a profit and not all makers had the skill, apparently.