Take Capital FM 226 unique tracks over the last 30 days. 12 tracks in common with 6music.
Or the more indie/rock XFM London with its 540 unique tracks over the same period including 226 with 6music.
Maybe a softer cored Heart with its 508 unique tracks and 22 in common with 6music.
And how many unique tracks did 6music play? 3,258. About 6 times as many. Of course you still need to like the music. I think the only one to compete on variety would be Radio 2, but their 2,392 unique tracks have a rather different audience profile.
"Those Charts In Full" as comparemyradio.com might say.
6music and CapitalFM
6music and XFM London
6music compared with Radio 2