I only play 2 characters and normally have all my Mythic 0s done by Wednesday. After that I come home from work do my Emissary WQs and then farm the Dune Scavenger and Leaping Veinseeker mounts. By doing this I have sold 3 BoEs and about 7 mounts totaling around 5 Million gold. So yeah I would say I made a shit ton during BFA. Before BFA I didn't play since Very Early Legion and only had 170k on my Account and spent that to reactivate my game time. So I was pretty well poor AF. I now have a total of 6,223,576g on my Account. If you focus on making gold you will make gold.
Mythic+ rewards will also go up by 30 item levels; however, during the first week of Season 2, rewards from end-of-run chests will be capped at Mythic 6 quality (item level 385), and the chest you open next week will contain Season 1 rewards if you do a Mythic+ run this week. (So, for example, if you do a Mythic 10 during the final week of Season 1, you’ll get a Season 1 item level 380 piece and 60 Residuum from your first Season 2 chest.)