Nothing Compares 2 U was her biggest hit. She did have a few other singles that hit the charts here and there, but nothing that really stood out. She was always kinda drawn back, like Bjork... sorta... she was also mentally ill (no idea what the diagnosis was), so that took a toll I guess as well.
She was never really big, like Spice Girls big, though the quality of her songs was levels above that. Still, she stayed kinda niche, no one actually talked about her in the past decade or so, unless it was regarding Nothing Compares 2 U, so... I guess she was just forgotten by time. Not the first or the last person that reached a peak with 1 single and then just slowly drifted away.
That is... so touching ๐ฅน