It's me (or you).
Put me on a Squier 5-string and a small practice amp, or a 5-string Alembic through a big preamp/power amp/Bag End cabinet mega rig, gimme a few mintues, and on either one (and both), I'll sound like me. Always.
I've played too many basses through too many amps to not know that this is utterly true. Granted, on nice axes and nice amps, I sound like a better me, but it's always there.
'Me' is a five-string with nickel roundwounds, good cables, and larger amp with great EQ. I know what I like, and what it takes to sound like me, and that's what I'll steer towards when it comes to buying stuff. Not too much bass, not a searing top end, but enough clear to hear the strings in the mids and high mids. Solid.
I totally think each of us has an embedded at a DNA level of what we think we ought to sound like. You can have a big pedalboard, buy any bass or amp you want, and sooner than later, we spin knobs until we hear 'me', and like snowflakes or each person's idea of a perfectly-cooked ribeye, it's totally different from player to player, and unique to each one.
Buy what you want, play what you want, but sooner or later my 'me' or your 'me' always comes home to roost.