Radio ban during 'Britney' era, she never was radio force anyways.
During her first 4 albums, she only released ...BOMT(in the end of the 1999 they removed leftovers from stores), FTBOMBH(#8 best selling physical song of 2000's), Stronger(1 of 3 songs that got certification in US in 2001) and MATM(best selling dance single) as a physical copies. Rest only had limited releases.
Later, she usually had huge debut weeks sales so would go to #1, but radio never supported her like Katy, Rihanna...
Better question, how Xtina didn't get solo #1 since 2000.