Some of the cost might come from buying a computer suitable for video editing, which I can imagine could be a couple of thousand dollars.
You do not need a really beefy computer to edit videos especially when you're starting out. A Canva Pro subscription is a couple of hundred dollars and will let you upload all your footage and then edit it within the browser meaning you don't need to have a powerful computer. If you grow your channel and your needs change then just cancel Canva and buy that bigger machine you need. Use your phone or something on the cheaper end (of cameras) like a GoPro to record.
And we edit on two M1 Ultra Mac Studios, as well as M1 Max MacBook Pros, all fully-optioned.
People vastly underestimate the time and expense involved with “just posting videos to YouTube.”
(If it’s such easy money, why aren’t they doing it…)