The bigger issue is pressure with steel loads. They tend to be very fast loads with high pressures which are not good for old double guns, their stocks or old shooters shoulder shooting them.
Steel is loaded to fast velocity to offset the quickness which it looses speed and energy. Slow steel performs poorly on game. When you think about shooting cost of three bucks a shell as high you are getting distracted by one expense. Yes $75.00 a box is steep but when you consider a box of shells a day would be a lot of poor quality shooting or one of they best days of your life it is not that much. I figure a day hunting cost several hundred dollars even if I don't shoot. Lost wages, gas, equipment, hunting fees and license, plus all the other expense far exceed shell cost. Shoot what works well and is safe for your gun. Saving 30-40 bucks on a box of shells is not that big of a deal.