Uh, yeah!
I mean, you need a bass for blues and a bass for classic rock and a bass for metal and a bass with 5 strings, and a bass with 4, and what if you feel like flatwounds today but roundwounds tomorrow? Honestly, you don't want to have to change those things, grab a different bass, and that's a beautiful wood, and what an awesome shade of blue, and that bass is SO comfortable, and then that one there, oh if i had that kind of money, and the list goes on and on...
Then there's amps. Which one is best for what venue? Might be a one-size-fits-all, but we all know that really isn't the case, so practice, sm to mid, and then decent sized. Then there's this awesome irig out to use your iPod as an amp - the ultimate practice amp. If you have good headphones...headphones...cables...different lengths for different situations (that sounded bad, didn't it), effects boxes, wah pedals, something to organize them all, di boxes, monitors, ooh, mixing might be fun...oh where does it stop? I need a bigger house...with a music room, oh, and recording? Where can I do that? Maybe 2 music rooms?
And then there's shoes...oh, they go with basses, and venues, and music styles, so they can be considered GAS, too...
Oh, btw, nobody needs 9 designer handbags. That's just silly!