It has gone into administration.
I got married in 1982 and we got loads of the stuff. Those were the days when freezers were rare and fridges very small. It sort of did a job, but I found that it made some foods 'sweat' and go limp. OK to save some leftover stew for the next day, but not much else.
We now have freezers and other alternatives - my cookathon portions are saved in any old container, then in the freezer.
It's main problems were that it lasted so long, over engineered so no ongoing sales, and its price!
I have not seen it for sale for years, but I do remember mum's 'Tupperware Parties' to earn her a few bob.
Sad, but not surprising.