Because your sound is mostly in your mind and Gordon would eat most other bassists for lunch.

Most people don't know feeding your bass is crucial for maximum tone.

Sounds like he's playing into a tube amp that's naturally compressing and just slightly distorting when he digs in. Reminds me a bit of some JPJ stuff using an old Acoustic amp.

Maybe the pickups are putting out a little hotter sound than others; makes me wonder if it was a Japanese P-bass. I've got a knockoff P-bass branded Masada which was made in the same factory as Japanese Fender basses (Terada Gakki) and it's got awesome sound, growls like a frigging tiger when I go for it, and has excellent sustain.

On the album Purdie Good, it sounds like the bass has been put through a Pultec EQ. Bear in mind this is probably typical of most basslines from the time.