...and why these discussions are endless...
.... and largely pointless.
About the only 'truth' is that there are folks with successful tanks under LED, T5 and MH. Anything else is speculation or conjecture. Lots of reasons why tanks fail that have nothing to do with lighting. Heck, I used MH for far longer than most people here (certainly longer than the internet geniuses), but ultimately switched completely to LED because it works better for me. At some point the debate will become moot because MH will no longer be made for the hobby; until that time use what you prefer with the comfort that they can all be made to work.