What you did took more effort than they were willing to do. for the journalist; "deadline approaching, weekend approaching. Double-check it on a few sites, seems like everyone agrees, screw it, I'm going home..." Some of them don't know how to do a patent search. Some don't even know they should under those circumstances. They also would not have looked at the original drawings to make sure it was data entered correctly, nor would they know the difference between a filing and the grant of the patent date, which are years apart for this item. A professional historian probably would, but not a professional journalist.
_____________________________ Give a man a mug, he drinks for a day. Teach a man to mug... The difference between an ostrich and the average voter is where they stick their heads.