If you've ever watched LTT, you'll know that his business is anything but passive. They own buildings, have employees, HR departments, R&D, and all that stuff. This sort of approach is probably not too different, except in scale, to huge media companies.
There’s very little passive about running a YouTube channel, and if you stop publishing then traffic to your existing videos will start to drop off over time.
I saw a standalone video ad with him the other day (on LinkedIn?) for Supermicro server products. It was clear from his voice that it was a paid promotion (not the same tone as a typical semi-objective modern product demo/review), but I'd guess that would have some reputation cost with some viewers. So I'd guess his company makes good money from that as well.