Corning sold the Pyrex trademark to some knockoff joint in China, and the new vendor’s glass is just glass. Original Pyrex is of course still available used, either online, or (much cheaper) at thrift stores, garage sales, estate sales, and the like.
Once you have lost your patent rights and your brand mojo, even profitability as a cash cow disappears I suppose. I haven’t followed ceramics for years, so thanks for the observation.