The physical stuff that comes with a game is kind of dirt cheap. It's small potatoes compared to other costs, and the elimination of it was really for environmental reasons and not really a cost cutting measure (although that maybe factored in a little).
Not saying that the overall point is wrong, but I don't think that's a great line of reasoning to support it.
But, the main thing is, vote with your dollars. If more people either don't buy games at 70, or wait for a price drop, then prices will go down... or they'll just cater more to the people who will drop hundreds of dollars on loot boxes. One or the other.