The reality is that Kodak etc wouldn't spend the time & effort to research and take a product to market unless some pretty ruthless tests showed it was provably better - this is where Kodak and others pulled ahead of the amateurish developer-tasters, who didn't have electron microscopes and microdensitometers, let alone emulsion research divisions to investigate the grain/ speed/ sharpness relationship. That Ilford, with a significant basic science research group at the time, ended up essentially making the same product as Microdol/ Microdol-X in the form of Perceptol, says far more about how accurate Kodak's pinpointing of the useful mechanism was. It's terribly easy to want to make folk heros out of some kind of supposedly heroic amateur chemists slowly poisoning themselves with PPD in their garden sheds rather than teams of white-coated researchers in large corporate entities coming up with elegantly simple and much less toxic solutions - especially because it doesn't fit easily with some of the popular (and often fairly well founded) narratives about mid-20th century corporate behaviour with regards to chemicals and their effects on the end user and the environment. Ironically, the use of PPD in hair dye (and other dyes) until very recently is actually a pretty clear illustration of that behaviour.
The other problem with people playing around with many developers today is that the 'tests' they do seem to lack even the most basic sensitometric controls & comparisons - and often rely on consumer grade scanners with questionable MTF and noise characteristics, which they then proceed to sharpen the life out of.
