“Sing that good”?
She’s a decent singer. As are tens of millions of others. No Linda Ronstadt. Not by a mile.
As described above, she had the right combo of writers, mangers, fashion, and attitude (not to mention the emerging MTV) in the exact right era.
Also as said, few thought she was “hot” or “beautiful”. Madonna had an “it” factor and this made her desirable in essentially a wanna-tap-that way. Quite simply, turn on the TV and she’d be there, squirming and writhing in a recent hit video.
Smoke and mirrors.
I was a teen ‘83 to ‘89. I was right in the thick of her popularity run. None of my friends thought she was anything beyond a bouncy slut with some undeniably catchy pop ditties.
(Me, I got off on her pre-success nudes that feature her with a snazzy bush. Love that shit.)