Madonna could have become a grande dame. An elegant, attractive older woman with a mature presentation.
She would have been great doing smaller, cabaret style shows where she focused on vocals and music, new interpretations set in a key for her voice as it is now.
She really could sing, and live, prettily. I've heard it in person. The Evita vocal training worked, until she let it all go.
She could have stunned and brought a room to its feet if she walked in with the class of a Debbie Harry or a Helen Mirren.
That's what I hoped for for her, not whatever she is now.
She might have looked like this (made by Grok from my suggestions).