You're arguing based on a false premise here - nobody literally wants free consumables, we want to not be required to do extra gold or reagent farming (or to buy tokens with RL money) just because we do high-end content that requires consumables and/or because we want to push our spec to the limit of its performance.
It is OK that consumables cost a bit, and that we would have more money over time if we abstained from using them. But slowly but surely being bled dry unless we put a lot of effort into farming gold/reagents is not acceptable when being in a mythic guild, especially a competitive one, is already a big investment.
Even in late Legion, when potions of prolonged power was dirt cheap and the rest of consumables were reasonable as well, far from 'everyone' used them all the time. I did a ton of heroic pug raiding on my alts back then, and it was rare to see the whole raid being flasked and double-potting, and that's with me getting into relatively decent pugs because of my mythic progression. Hell, even though I made millions of gold in Legion thanks to an army of alts with the mission board, I didn't bother using prolonged power on every single trash pack in M+ for example.