I don't see any cement board anywhere. I do see old old drywall that is crumbling. I also see at least two prior repairs and a shower surround that is well past its usable life time. Time to say good bye to that shower.
The cast iron tubs can go forever but the finish that is on them does not. If the blue has worn out its welcome then now's the time to change it. If you like the blue then keep it. You will never duplicate the original finish of the cast iron tub if the day ever comes. Those porcelain finishes can not be duplicated in the field.Also, if it *is* a cast-iron tub, what do we get by ripping it out and replacing it?
Yup.Also, to clarify, when you say "acrylic" you're referring to a fiberglass body that is "acrylic capped"? Something like this:...