I covered everything you mentioned in my second paragraph. Maybe you missed it. I do agree with your bit about finding a niche or trade as to at least make the prospect of doing something over and over enjoyable. And I wish I had the confidence to say I knew everything. If I did I wouldn't of made this thread. I'm aware of my short comings; why I'm asking for advice from people who had been born before me.
If you know what you want to do, meet and talk to a person that has reached a point in their career that you would want to be at. If you want to be an English professor, get to know one. If you want to be a detective, get to know one. If you want to be a member of the clergy, get to know one. Talking to anybody deep into a field you want to be in will teach you more than any book can.
When I was a musician just learning and trying to get things sorted out I was lucky to be in a band with an older person who had become rich doing it and pretty much a pop star in his time (earlier years as teen and twenties) having been on Ed Sullivan a lot. He pretty much said what everyone is saying on this thread and seriously wished he had lived a normal life, in obscurity, and finding a safe job. Placing yourself high on the Billboard charts put an extraordinary amount of stress from the managers and record company pushing you to write and record songs and get there again. No matter how many times his band had a hit, the bar was put up higher and the stress increased. He pretty much told me that there were no laurels in the music business. I knew, deep down inside, that what he was saying was the absolute truth but I didn't want to listen to him. In my head I thought if the "other" guitarist in my band could do it and get a few top 40s, so can I.
He told me about how awful it was to be around security and have girls rock your limousine back and forth and pull at your hair and clothes. He truly hated that after a very short time but then had to endure it for years. But to me, being young, I thought this was a very cool dilemma to be in.
The stress of the road, and fame, contributed to his drinking which eventually killed him a few years after our band broke up and then I understood. He could never get back those years where he said a person should be discovering themselves and getting a foot in the door. Being a big popstar is not discovering yourself and almost every person who has attained that realize that it was more luck than anything else. From the viewpoint of small town musicians like me, he had made it and "should" be happy, but from his perspective he lost a lot of good years being put into this vortex of fame, fans, and ultimately unnatural stress. So when I see a Miley Cyrus or Britney Spears fly off the deep end, I totally understand since it happened to my bandmate.
So it's one thing for a musician who had not made it to tell me to get a regular job and life and do music as a hobby, but it was amazing to get a chance to get to know this man who had gone big and still said it's better to get a job and regular life, and that it was his one big regret that he never got that chance. We all need food, water, and shelter but another need is for a reasonably sane life, and popstar (my goal as a young person) is not reasonably sane.