I think Gary Willis might have invented the Ramp. Personally I can't see much use in it as the space below the strings doesn't bother me. Why do you think it would be useful? I've been playing 34 years without one. Glad to see another Spector user. I have a fretless 5 string with a peizio pick up along with a soap bar.
For a list as to why it would be useful, you can read the paragraphs on it at the beginning of the thread. You've been playing for 34 years without one, but have you spent those 34 years playing with four fingers and a very light touch? I played without them for ten years using regular fingerstyle- when attempting to switch over to multi-fingered picking, I had a hard time for a while. I popped a ramp on my bass and I saw instant results and benefits.
If you're just plucking with two fingers and a normal attack, the space below may not bother you at all. Using three or four fingers, which require a lot more consistency in attack if you don't want it to sound like crap, combined with using a very light touch makes that space much more noticable.
Again, they're not for everyone, but for some, they are a huge benefit.