Ilford still have a glass plate coating line in use which uses a modern coating head, anyone who's been on a factory tour will have seen it demonstarted. However the cost of coating plates is very high and Ilford's production is mainly for the Nuiclear industry..
The last production of regular Ilford plates was some time around the 1970's I remember being given a box of outdated FP4 plates with my first LF camera in 1976.
I've recycled old (unuseable) glass plates as ground glass focus screens and even as glass inserts for Durst negative carriers. One problem now is that for health & safety reasons the minimum thickneess of glass sold to the public is 2mm (in the UK) which can be a little too thick for some plate holders.