Most of the comic companies have gone to using the cheaper paper stock for their covers that they use on the interior pages, and they didn't bother to lower the costs.
There is one smaller comic company (Alterna Comics) which is using the really cheap paper stock and only charging $1.99 per book. So, it's definitely possible.
However, you have to wonder how that may effect sales. No one except the most diehard comic fan is buying that companies' books. Some readers may be turned off by a comic which looks to be the same paper stock as a newspaper.
I mean, I'm pretty sure the paper stock was higher in the mid-1990s, when mainstream comics were printed on that glossy paper.
They are charging a bit above the inflation rate, as a Marvel Comic was $2 in 1996, and checking the inflation rate, it should be roughly $3.25 in 2019 after inflation.
I'm wondering if comic companies have raised their prices a bit above inflation due to losing readers though. Sometimes if a business is doing worse, it will raise the prices, to gouge the loyal customers it does have in order to make an up extra profit from lost overall sales.