I think it is all about the levels of engineering brought to bear, by each maker.
Early Webleys and BSA's, were airguns built by Firearms manufacturers, so engineering tolerances were very tight, and high levels of engineering were brought to the table. That engineering ability dropped off in the 1960's, then again in the 1970's , when guns could not keep being manufactured to such high standards, whilst the companies still made money.
I think that the advantages of a fixed barrel, outweigh, some of the disadvantages of break barrel guns. The standard of the Tap in a 1920's BSA Standard is massively better than the standard of the Tap in a 1970's Airsporter. The first doesnt usually leak air, whereas the second ALWAYS leaks air in my experience. I know which one I would rather have
Problem is that all these guns are now old, and have varying stages of wear and tear. It is hardly fair to compare a Webley Mk3 with a HW77, say as the latter gun is so much newer than the Webley.
The reason I collect older guns is because of the high levels of engineering and manufacture that went into them, and a good tap loader always beats an average direct barrel loading gun IMO.
Lakey