You could speak to a lawyer about litigation against the inspection co.
Since they misidentified the polybute as pex you may have some recourse.
I just sold my house here in NJ and I had put polybute in it. The realtor
made me include a statement in the paperwork so any potential buyer would be
aware of it and could make a decision about it. They are presently having it
replaced. In some states there is state aid in helping with this, you might
look in to it.
Oddly enough, in nearly 20 years of using poly, I have not had one leak
occur. I've had very good luck with it.