Because you don't want to go through the hell that DRs Laura and Sandra went through? 
I've been through plenty of hell on this house already. About twelve years ago a painter started a fire, which damaged one corner of the house, all three floors. It took forever to get it all fixed, largely because of the lack of professionalism and commitment from so many in the building trades. I wish I'd known Marvelous Matt then!
The master bath is on the second floor and was part of an addition put in by the previous owners. The existing tub and shower COULD be torn out, but getting a new unit--or worse, a porcelain tub--up a narrow, twisty staircase wouldn't be easy. And, of course, that would mean lots of patching. I'm trying to FINISH this house! No new projects! That's why it's not an option. Jeanne just couldn't handle it at this point.
