I know that Last Resort is their biggest song by far but that is because it's one of the most popular songs ever, in any genre. Their other stuff is still huge.
The band has many songs with hundreds of millions of streams on Spotify and many Top 10 records.
If that band is a one-hit-wonder, than 90% of Graspop headliners and 99% of bands on the line-up are basically 0-hit-wonders.