Print runs have changed significantly in the last decade or so. Back in the 80s, 5000 of a card run was extremely limited. Think of the Tiffany sets and how "rare" and expensive those were. In the early 90s, Donruss was inserting Elite cards at 10,000 copies each, but you never pulled them because they produced BILLIONS of base cards. Well, maybe a slight exaggeration, but it seems like billions!
50,000 can still be a relatively small run considering how much of a product is made. Given I only found about this Thomas card a few years back, I would question if 50,000 were made. Sometimes those "good ideas" went South fast and production halted when sales didn't keep up with expectations. Same goes for those porcelain cards people have been talking about. I think the prints runs advertised are much greater than actual cards made.