They've been doing this with TP for ages.
First, TP rolls had 300 sheets. Then 250, then 200, then 150.
Somewhere about the 200 sheet era, they came out with Double Rolls, with 400 sheets, which then declined to 350, then 300, and some are now 250.
Now we have Triple Rolls - haven't looked at the sheet count, but betting it is somewhere around 400 again.
And of course you have to compare single ply, double ply, etc, for value.
I was just shocked to notice the bigger hole in the middle, because that seemed particularly devious.
Suave Shampoo has been one of the more stable ones, but the bottle still dropped to 13 oz instead of 16 over the course of the last 10 years. But periodically (usually right at the time of a price increase), they'll do a 33% more free promo, where they have a great BIG bottle (bigger than their usual large size), and it will only be $.10 or so more than the price was the week before for the regular large size. They'll carry that for a very short time, and then the price will stay higher, but the amount will drop back down. I stock up on the big bottles, when they run those promos, because it is less per ounce then.