They've been doing this though. They put the songs on recurrent to keep the charts moving. Instead of waiting ages for a huge hit to fall completely off it's just easier to take them out after 20 weeks and they've fallen below #50.
So once Radioactive dips below #50, it's just gonna fall off even after all this time? A mess
DAYS INSIDE US iTUNES TOP TEN (can't find OOTB data)
Dark Horse - 140 days
Roar - 122 days
Teenage Dream/Firework - 107 days
California Gurls - 97 days
E.T. - 89 days
Last Friday Night (T.G.I.F.) - 72 days
Wide Awake - 71 days
The One That Got Away - 52 days
Part of Me - 38 days
Walking On Air - 4 days
Unconditionally - 0 days
Birthday - 0 days
DAYS INSIDE US iTUNES TOP TEN (can't find OOTB data)
Dark Horse - 140 days
Roar - 122 days
Teenage Dream/Firework - 107 days
California Gurls - 97 days
E.T. - 89 days
Last Friday Night (T.G.I.F.) - 72 days
Wide Awake - 71 days
The One That Got Away - 52 days
Part of Me - 38 days
Walking On Air - 4 days
Unconditionally - 0 days
Birthday - 0 days
DAYS INSIDE US iTUNES TOP TEN (can't find OOTB data)
Dark Horse - 140 days
Roar - 122 days
Teenage Dream/Firework - 107 days
California Gurls - 97 days
E.T. - 89 days
Last Friday Night (T.G.I.F.) - 72 days
Wide Awake - 71 days
The One That Got Away - 52 days
Part of Me - 38 days
Walking On Air - 4 days
Unconditionally - 0 days
Birthday - 0 days
This can’t be
It'll go on the recurrent chart to make room for other songs.
AMAZING! Another All Time hit is coming 
updated