I'm still calling BS - I've been doing this for a long time (8-9 years). I know how much effort it takes.
With the current state of stolen packages epidemic/Amazon not refunding, qla, BC, shutdowns, etc. there's no way to profit that scale of money without having a large network of Amazon accounts with 10+ Amazon CCs. And at that point it becomes a full time job to manage - there's absolutely no way they're doing this without spending 30-40+ hours a week on it. Maybe their real "full time" job is really a 10 hour/week job allowing them the time to do this.
I agree 100% about the current state and the effort. Some people use to manage 100+ accounts and then were shut down and started over. I imagine a couple dozen accounts feel like a walk in the park.
As far as a job, they multitask and are online during working hours. Pretty obvious when you see them on Slack, WA, TG, Discord. Even with AUs and VNs, you do tap out CCs. Amex Amz and Affinity are now capped. Chase and Synch aren't if you can get a large CL. Qurately bonus spend for Amazon is limited. From there it's 3% cards. As far as MSR, there's other couch ways to meet it, without the hassle, if you're going to do BC deals.