Based on my years of experience dealing with people like Morrison (i.e., alcoholic drug addicts) on a fairly regular basis in the ER, I can tell you that if Morrison, Cobain, Hendrix, et al had not died young, they would have probably just died a little older...
That is, of course, after they left a still longer trail of emotional suffering behind them. The end is generally the same, and the price paid by the survivors is always forgotten by those who would idolize people like Jim Morrison.
At the end of the day, Morrison was just a nihilistic, narcissistic, self-absorbed little punk.
Morrison was all you said and more. He was very talented.
The age old argument about artists' talents and their personal life and whether the latter negates the former has apparently been won in your mind but not in mine.
And your experience aside, we know that people like Morrison come to bad ends. But not always. And not uniformly.
He came from good genes, perhaps his end would have been better.
We just have a different view on this. Surely you would allow for that?