Sorry if someone's already said this, but I haven't heard the take yet and I wanted to share my theory:
I think Jeremy is nigger rich. I think he has spent his considerable earnings in the same way as a soundcloud rapper who got a few big hits and started getting money does. If a nigger rich person gets cut a 10k check, they spend it on clothes, shoes, jewelry, etc. If they get cut a 50k check, they spend 100k on a car. If they get cut a 200k check, they spend 500k on day crib n sheit. And when the money dries up, because it's unsustainable, the bill comes due and they have no way of paying it. His watches, the plane(s), the RC track, the big house, the vanity projects, and so on, are all him spending like a darkie who got a couple big hits on soundcloud, or got signed to a big sports team for a hefty contract.
This would explain his apparent growing stress, and his desperation to inflate his view count to fraudulently misrepresent himself to advertisers: it's not that he isn't hasn't earned a lot of money, or that isn't still earning money, it's that he spends it as he gets it, and takes out loans against his future earnings, which are now beginning to dwindle. With revenue contracting, the debt he's taken out is likely becoming, or appearing to become, a very serious issue. This appears to be supported by his home equity loan, but I wouldn't be surprised if that was just the tip of the iceberg.