Like others have said, it depends a lot on cost of living, production cost, etc. It also depends on what you are able to do outside of youtube. For some people, earning $2,000 a month of youtube may be enough, for others, they can earn more with their job. If you have a good job, where you are building experience, connections, etc, it would be hard to quit it and just do youtube. Too much uncertainty. It would also depend on what field you are interested in, if you want to do something in film production, youtube might actually help you, but if you want to be a construction manager or a programmer, I doubt putting "Youtube Star - 2014-2016" on your resume would add anything.
I've seen channels with over a million subs, that have around 100-200million views, over about 2-3 years. If you are earning $1 per 1000 views, that's $100-200k total over 2-3 years. A professional job can earn similar, only it will last longer. But with youtube, you could grow bigger, and start earning thousands a day. Plus it may be less demanding than an actual job.