In a few months only mats will be worth anything. At this point we have people with tens of millions of gold and people with just a few thousands. A flask takes tons of mats to make, and they will sell for well over 10k gold each, so the casual players won't afford them. When people realize that the rich guys will always take buying from the AH over farming their own mats, the prices will go even higher, then casuals will notice how expensive flasks are, and they will pick up alchemy and make more flasks, driving the prices down again.

I'm aware that the LS chain can be xmuted up all the way up from GIO. This is great since it means ultimately you only need to track/acquire one item. The procs can certainly increase your profit margin, but as I said in my top-level comment the profitability of the whole endeavor is server-dependent. These numbers will of course vary from server to server, and for some it might be worth it.
The world quests aren’t necessarily bad, but they aren’t good either. I wouldn’t mind killing five of a type of monster or fighting one particular boss a few times, but after seven or eight, it starts to wear pretty thin. But going from levels in the mid-20s can take nearly 30,000 AP, so you’ll need more than world quests if you want to get your heart up in a reasonable time.

Like I said, engineering is the best when you aren't worried about making gold. The Loot-a-rang is super useful, nitro-boosts are nice when they don't fail, and the glider cape enchant is nice too... you get wormholes to Pandaria, Draenor (make sure you have a glider), Legion, and Argus (as well as a couple old world teleport locations)...Jeeves (and to a lesser extent Reeves) and MOLL-E are also super useful (bank and mail access anywhere, repairs, etc.).
This top-end difficulty was missing entirely from Legion’s first raid, Emerald Nightmare, which was cleared by top guilds in around 11 hours. Meanwhile the first guild to clear Uldir’s hardest difficulty, Mythic, spent somewhere around 70 hours attempting to kill the raid’s eight bosses. Even after all that time, the guild, Method, still had members say they loved the raid, and that it was one of their favorite in recent memory.
Good news for WoW fans! According to what know, World of Warcraft's latest expansion Battle for Azeroth has been as one of the best PC games in 2018. That at least tell us that WoW is valuable and WoW deserves our money on WoW gold. At the end of this year, we are lucky to experience ancient potion called "Elixir of Tongues" which allows us to understand the opposing faction in chat.
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.