Absolutely! YouTube is now my career 100% (actually 168%). But I'm strictly behind the scenes at the moment.
For the kids, it's part time. For my wife, it's casual, helping out now and then.
We hope the wife can quit her job in December and we go all in to Youtube.
In my 26 years in IT, telcos, cafe, IM, YouTube is by far the most challenging, the most exhaustive, the most fun, and the most profitable job ever.
But you have to go all in. I would say give it 100% but that is not enough. You need 150%-200%.
About fun, it is over-rated. Perhaps when you are 15 living with the folks with all bills paid, washing done, dinner ready for you on the table, ye, fun is great. When you've got mortgages, kids, bills, fun takes a back seat to supporting your family and having stable income. If there is fun in your job, ye that's great, but more important is satisfaction at reaching your goals, supporting your family, and being successful (however you define that success).