My bathroom should be big enough for a swimming pool

The bathrooms in our house aren’t all that great.  They’re not awful or anything, but they’re not the spectacular bathrooms I would like to have.  The downstairs half-bath in the hall is fine (you can’t ask much from a half-bath, and it does its job),  but upstairs is a little disappointing.  Our master bath doesn’t deserve the name, but there doesn’t seem to be a whole lot we can do about it.  I mean, yes, we could replace the vanity and upgrade the shower (and put in a nicer floor), but it’ll still only have a single sink and a walk-in shower with no tub.  There’s no room to do anything bigger.  We’d have to do MAJOR renovations to the whole upper floor, like add rooms over the garage (which would mean a whole addition to the house), and that’s just not likely with our current plans.  The main complaints I have about the other bathroom upstairs (the one I use) are that the bathtub is too small and the water pressure SUCKS.

So naturally, I sometimes find myself daydreaming about the perfect bathroom.  A few years ago, we were in Boulder for a work thing, and we stayed at the St. Julien Hotel.  That bathroom was incredible.  The tub was super long and really deep (I could practically swim in it), and the shower was awesome. I think that bathtub might be my happy place.  (Serenity now!)

You’ll have to believe me. The picture doesn’t do it justice.

Why are standard bathtubs so small?  According to Wikipedia, average height for women in the US is between 5’4″ and 5’5″ (and you have to be shorter than that to fit comfortably in a regular tub) so the evil bathtub industry clearly has something against baths.  Which seems to be contrary to their interests.