I collect a lot of concerts. But while I stick to only one band's shows, I can imagine there are lots of other people who collect a lot of bands. Those people would run into songs greater than 25k.
I just did a very rough, arbitrary calculation:
25k songs with an average of 6 mins per song would work out to 2500 hours of music.
If we assume 2 hours of listening time per day, then it would take 1250 days to listen to all that music. That would work out to about 3.42...