Whoa buddy! Calm down. (Referring to other parts of your post.) In my experience, one good trick really is all people are looking for... non-bassists that is. Hence, to get work and be paid to play, you really only need to be really good at that thing, not marginally good at a variety of things. But you don't agree? That's fine. Cheers!
So you are saying that "all you need" is to get work and be paid to play? That's it? I presume this means you don't need any trick at all so long as non-bassists are impressed enough with what you are doing that you get hired. I know quite a few bassists like this. They own one bass and some old rig from 20 years ago, they work all over town, and make plenty of money.
I'm not going to say that doing that is "wrong". It works for them. But I'd call it "in a rut". My gripe is with this phrase "All you need" that everybody likes to use. To me they are implying that this is all THEY need and therefore it's all ANYBODY needs!
My musical needs go beyond simply getting a gig and collecting a few bucks. To me music is art and art is all about creativity. If I had to play the same old bass and same old rig with the same old music over and over just the same way until I could barf, I'd die. One of the most wonderful things about music is it's always different. Even gigs at the same old places tend to different each time. Music isn't static, it's constantly changing with people constantly coming up with new ideas and sounds.
So to me, one of my needs is for creativity. I NEED to be creative! Just one simple trick would not allow me to be creative the way I'd like. I want a whole BAG of tricks to pick and choose from! So if you say about yourself: "All I need is one good trick!", I can say sure, that's you and you get to do what you want. But when someone tells me "All YOU need is one good trick!", they are saying it's all *I* need and I'm saying that's simply wrong because my needs are not that limited. And if you start to imply "it's all anybody needs" then that is wrong too because I'm somebody and I need more.
My main axes are fretted and fretless G&L L2500s with actually MORE buttons and switches than they had originally! Scary, no?