The "diaper bag"

I was thinking, oddly enough, about diaper bags.  I know this seems to be a weird thought or even a random thought on a Sunday afternoon. I thought about how diaper bags hold everything a baby needs: diapers, toys, bottles, wipes, etc. 

Now let's grow up a few years and think about this a bit further.  Isn't a purse like a diaper bag?  It holds your billfold, keys, and anything else you may need for the day.  So why don't we call a purse and adult diaper bag?  Well, it's probably because we may not need the diapers anymore, but technically isn't it the same idea?

I warned you it was random.  I was carrying something for someone and the fact that I had to carry the necessities for this person made me think about diaper bags and carrying necessities for babies.  Ah, randomness, it's where we thrive. :D