Assuming unlimited fundage, answer is null.
As has been mentioned, some people like to collect things. Comic books, stamps, shoes. Bass guitars. If you're Jay Leno, cars and motor cycles. I figure if you love it, and you can afford it, what does it matter?
Others can't see the point of owning more than you need. That's not a collector mentality, it's a utilitarian mentality. Makes perfect sense, if making sense is important.
I'm a collector now, but spent the early part of my career with only one bass. Didn't want more. Didn't need more. But I couldn't afford more either.
Now, I'm in a funny position: I can afford more, but I actually need more too. Gigs that require more than that one bass needed back in the day. But it's the collector mentality that really drives it. For me, bass guitars are more than instruments, certainly more that just tools, they are objects d'art. They are just as cool hanging on the wall in my studio as they are hanging on my shoulder at a gig. And there's always something one of them can do that the others can't soundwise, giving each a sonic personality that affects the way I play.
So, for those of us who can do anything you want with those two identical P basses, God bless ya. It's a great approach. I'm doing something else, but I'll still be cheering at your gig.