You're grossly underestimating the effort. There are many ballpark measurements, but a common one is one man-hour of work for one minute of video. It's an open market and you're literally competing with the world's best.
However, I've seen enough people babbling into a 720p web cam already having a 10k subscription base to assume it's possible to start something without spending whole days every week on the channel.
Sure, but for every channel like that with 10k subs there'll be another 100 with no subs. It's a reasonable starting assumption that you'll need to put some effort in to video production if you want to start a yt channel.
Unless you are extremely lucky or already have things set for you, building an audience is a very long-term grind, and typically a large percentage of those with some potential get burned out after 1, 2, or 5 years.
(None of this to say you shouldn't try, especially if you love the work... I enjoyed editing video since grade school when my Dad first bought an analog video capture card so I could dump a few minutes of VHS footage into a video editor and make dumb family videos.)
Edit: on second read I realized the tone of this comment could be read as dissuasive. I wanna clarify that I mean the opposite, I do support you in trying to launch a YouTube channel, I know far too many people who I think would make for great YouTubers I'd watch! But I do feel like you're underestimating aspects of this just based on a figure estimated by a web-site which probably doesn't have fine-enough grained access to YouTube data anyway and I think it would be better to come into it with realistic expectations.