Those large sizes of shampoo, conditioner, shower gel retail for about ¥6,500~ each if you walk over to Isetan or Barney's in Shinjuku. The body lotion is of course more expensive.

So, you can see why they would not want to offer them to upgraded/award suite guests, as even though the hotel undoubtedly pays much less than retail, the stuff is not free. Someone paying a significant amount for a suite perhaps would get them.

Why not just use the small bottles, and have them replenished frequently? Perhaps hoarding some away in a suitcase each day as well...