There have been female superstars after Madhuri namely Kajol, Aishwarya Rai, Rani Mukherjee, Katrina Kaif, Deepika Padukone, and Alia Bhatt. Just being objective here.
Some did have that craze as well for example Deepika from 2013-2015, Katrina pre-2013, and Alia Bhatt's solo films becoming blockbusters like Raazi and Gangubai.
So whilst not taking away credit from Madhuri, the last female superstar is too hefty a claim.
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