There's a major difference between marketed white, broad spectrum and full spectrum. Could be those early white LED weren't even remotely broad spectrum, Know that the combination white plus actinic o3 blue of the 80s weren't running broad spectrum for the whites. Figured that out when I started selling full spectrum for reptiles which could have been used with fish yet don't recall any trying with coral. Infancy when it came to understanding lights then and I think we are still learning.Of course the corals will still grow - white spectrum has blue in it. There’s a reason why everyone went to 20k radium MH bulbs. Also 30 years ago there wasn’t much to choose from. Most MH bulbs were 6500K and then as reefing started really growing lower spectrum bulbs came out like 12K and 20k Radium (although the radium was probably closer to 15K which is what AB+ is about).
For an experiment, go and filter out all blue (annythjng under 500nm wavelength) and run just reds and greens and see how much the corals grows.
Since Radion have all channels then when all used I believe that's at a minimum broad spectrum from speaking with Ecotech few years ago. Believe their whites also but not sure.
Key is working with what one has vs ditching and spending my point. Plus DLI might be legit. Believe that's why I kept an anemone thriving in the 80s although might lighting was far from adequate yet duration around 14 plus hours. No clue what they were other than salt specific and sold for corals. 80s more foggy than the 90s.