There are various shades of gold farming, though I am not sure what is hot right now. It is probably the closest to anything you can do as a daily grind job with an immediate and regular payout, and you would be far better off doing mechanical turk or skill selling websites if you want to make money online.
You can buy and resell games, fix devices and maybe build cool parts, though margins are tight (gamers are by and large incredibly frugal bastards compared to almost every other hobby -- I have full soldering gear and the ability to use it, some of the gaming stuff is at least vaguely interesting too, I do anything but deal with gaming types in that world though).
There are means of gambling on computer games as well, though fly by night would be so far up from where a lot of that is now that it might as well be in another solar system (I really seem to be into my space metaphors and analogies lately...). You can gamble on "esports" things fairly cleanly (though compared to more conventional sports it is still back alley) but as far as putting up an ante and taking it if you win then not so much.
With regards to youtube and co I would go one further. The amount of people that are big now tended to come up during the wild west days where you could cut 50 different unrelated films, music tracks and other games into a video and nobody really cared. Equally right now youtube seems to be making a push to be TV alternative (already there for me but there are still more to get) and that means those that get pushed seem to be those with lots of regular content, every day -- build it and they will come was never really a thing, built and make sure there is new content was but now it is build it and make sure there is new content every day near enough is the new norm. As you probably don't have a video production team (watch all the biggest channels, they will either be old school news stations with the video gear and ability to do fast turnaround or incredibly simple to edit) then you are unlikely to be able to compete there.
There is of course scope for someone to come in with something new, or to beat out any that came before. Always is for anything. Reliably being able to do that and make something worth speaking of out of the gate? Hahahaha... classic. Maybe you could put a reel/demo/whatever together and make a pitch to some sites or, horror of horrors, a multi channel network (by and large I doubt I would piss on any mcn out there if it was on fire) with the idea for a one a la traditional films and TV but good luck with that.
Millions might be a bit strong, though it is going to need to be a lot. If it is not millions then you also get to push your own adverts, your own merch, maybe all those tip cup/electronic begging sites (paypal donate, patreon and such like).
