I'm in the road of reducing my 4 basses to just 3, the essential ones:
1. Fretted electric (the most standard one)
2. an acoustic one (when no amp is found, or park playing is planned)
3. a fretless one
IMHO those are the exponents in the whole bass world and I plan to just own 1 of each. All 5 strings, because that's what I've chosen after having owned 4, 5 and 6 stringed instruments.
The plan is to sell both of my 4 stringers and buy the fretless 5 to complete my life

(already have a woman, a PC, an amp, a fretted 5, an acoustic 5...)
I don't see the point of having a lot of basses, but at least 2 or 3 variations is a lot of fun... IMHO.
Mathematically:
you buy your 2nd bass and you'll have 200% of the basses you had before.
you buy your 3rd bass and you'll have 150% of the basses you had before.
you buy your 4th bass and you'll have 133% of the basses you had before.
you buy your 5th bass and you'll have 125% of the basses you had before.
now we can see that if we keep buying basses, the increment is even more tiny.
anyway...