Tbh high prices of enchants / gems / flasks / augment runes / food buffs are mostly an opportunity for casuals to make gold. Majority of them don't use these for themselves. How often do you do casual content and see casual players use flasks, gem and enchant their gear? I rarely do. It's common to pug a normal raid or similar content and see people ungemmed / unenchanted and using no consumables unless someone drops down a feast. It's simply not necessary and not required in casual content and people don't bother. Not even mentioning more casual levels like lfr and open world content.
I think that's server dependant. I make a lot of Golems, but the price on my server is high enough that you could buy all the living steel and still make about 20K (almost 200kg on AH). Its just that you proc all the way up the chain. You proc 20% of your trillium, and then 20% of your living steel. SoH and Ghost Iron are such low effort farms, too. 20% of 180 Trillium Bars at 500g is 18k more profit, 20% of 150 Living Steel at 3500g is another 105kg. That's an extra 25k profit per Golem. If they stop selling stockpile them for the next expansion, they always boom with the price of herbs. And a consistent 20% proc rate is the opposite of RNG, its extra free stuff as a benefit to completing an extra quest (not to mention for new alchemists the investment of leveling Vanilla Alchemy). You're looking for some get rich quick scheme, where the real way to build wealth is patience and volume. No market is going to be viable because you want it to be. Only because you make it viable.