Pretty sure that isn’t what he said at all.
Rather, what he said was due to the bloated loot pools, layers of RNG, and no bad luck/duplicate protection he got zero upgrades.
In fact, I’ve seen plenty of people complaining about the exact same issue in Heroic+ and Mythic+ but you want to disparage the OP because the content he did was ezmode? He didn’t even say anything at all about “Mythic raid gear” and pointedly stated he was looking to upgrade 355 to 370 items.
See the thing is, we previously had smaller loot tables that made it easier to target upgrades and also had currencies you could earn through a variety of content that you could use to purchase the okay upgrade of your choice. In a reasonable time frame as well. We also, for a time, had a system whereby you could upgrade the item level and stats on the gear you had using an easily obtained currency to help even out your bad luck.
Now we have RNG, enormous grinds for some RNG, an even worse grind for a specific item, and you can purchase the option to try your luck with RNG over again.