No, they were not. This is pretty basic calculation that was already explained quite well.
I’m thinking they may have been generous…
The need for additional rubber in the sidewalls has already been pointed out. But what you are completely missing is that in many businesses, the cost of materials is not the primary driver for price of the goods being made. In this case, it takes the same CapEx for molds and equipment, the same amount of labor and the same overhead costs to fabricate a low profile tire as it does a “taller” one. Hence there is no significant cost savings at a finished goods level. Put the conspiracy theories to rest…