Can you imagine Paul Simon or Joni Mitchell being able to create what they did while holding down a career in accounting or engineering? Maybe they could. It seems unlikely to me.
But it begs the question: what's the ideal relationship between business and art to make the art flourish while keeping the business worthwhile?
Regarding your "can you imagine. . ." question.
I read the most interesting and wonderful true recollection of life in the early sixties "artist community" in New York. Mary Travers (I think) was reminiscing about the time when she, her group "Peter Paul and Mary" Gordon Lightfoot, Bob Dylan and too many others to mention were still "undiscovered."
The only way they were "making a living" on their music at the time was to pool resources and be a true "community of artists."
She recalled that on most songs, (the one she remembered in particular was "Early Morning Rain" by Gordon Lightfoot,) when someone would write a new song, there was none of the possessive fear of it being played by others. EVERYONE was playing everyone else's music hoping that SOMETHING would come of some song.... no one knew which ones. Everyone was thrilled to have his/her songs played, and everyone would excitedly listen to anything that might make an impression so that they could perform it.
Two key points about this stand out in my mind.
1. They were all willing to live like musical gypsies for as long as they could without any real assurance that they were going to "make it."
2. That sense of community sustained them and created artistry that cannot be sustained (in my opinion) by money and fame. I'm convinced that that "community sustenance" is as important as financial sustenance, and I'm convinced that it is entirely "lost" to this generation of artists. At almost every level, music is about "me, me, me, and more me."
I agree that some artists have to "make it financially" for music to keep providing hope etc for other artists. But I'm also convinced that the (usually false) idea that being a "successful musical artist" is a "license to print money" is damaging to the art.
It is (as you said) a BALANCE that needs to be struck.
Which leads to your question about whether there is an "ideal balance" that can be struck. The answer is "No, - not an ideal balance." I think that in place of an "ideal balance," we should be seeking ANY WORKABLE balance. I think the musical world is so "money driven" right now that balance is out of the question. I think that what works in our favor (as songwriters and artists) is that the system is sooooo "out of balance" right now, that it is actually "bad for the business." I think that someone (and I'd love for it to be me, but I have no viable ideas) will find a way to make a LOT of money by finding a balance where the artists have more control and a more fair "cut of the take."
That imbalance happens in every business. When a business and/or an industry becomes overly consumed with the profit margin, they "turn the screws on the profit machine" until they actually start costing themselves money. It goes on until some competitor exposes their unprofitability by "loosening the screws" and putting them out of business by out competing them.
I don't know if we are "due" to have this happen in music. . . but it's bound to happen in every industry, sooner or later, and music is (imo) no exception.