There were huge numbers of supporters at Obama's and Trump's inauguration. Almost no one at Biden's.
I am not going to argue as to whether Obama had more at his 2009 inauguration of Trump had more at his 2017 inauguration. If Trump had not had the election stolen, I believe Trump would have had the most ever supporters at his 2021 inauguration of any President in history. Trump won a lot over after he was elected and did what he said he would do.
No US President in my life time, had rallies in other countries for Trump like Trump had in support of Trump
MILLIONS WORLDWIDE RALLY IN SUPPORT OF PRESIDENT DONALD TRUMP