There is a company I use here in L.A in less then an hour the re glaze a bathtub, look just like a brand new, and the not that expensive ( apex $200.00) considering the demolition and installation of a new bath with the added cost of new bath tub.
Check in your area for re glazing contractor
I fund this link for you on Google, never use them or talk to them, this is just to give you an idea
reglaze contractors
Good luck