Or it could be something simple like their webmasters having an "oopsie" moment when doing their updates.
Still, it seems strange for all Tamiya kits to just vanish from their site. What could have Tamiya (or Hobbysearch) done?
There was a story I was told of Fujimi being kicked out of the Japanese modeling consortium for not following some rule. They were banned from the annual Shizuoka Hobby Show. Only years later there was some kind of reconcilliation. The "Big T" I assume are more cautious than that.