In 1990 they sold 5 dollars per stuffty tiny brick car and it probably only took 1 dollar to make.
Lego sets have always been the same price, back in 1990 it took 400 pieces (max) for the largest sets.
That would be about a 30 dollar set today, nothing has changed in pricing, just the need for pieces.
They need to make molds which takes money.
They also need to pay for printing, packaging, shipping, and other.
The plastic alone now costs much more because of color matching.
Those would be the only things to change the cost, not the bricks themselves.