Yes, SNES and N64 carts cost more to manufacture than Disc based games do. It wasn't just this though- nintendo had some pretty draconian royalty policies in place as well. New games could and did cost up to $30 more than comparable PS1 games back in the day, and you can't tell me that was all just the cost of the cart itself.
But that's besides the point. What the OP was trying to point out is that since the advent of disc based games (say, 1995 or so) the cost of a AAA game has only risen 20%, from about $49.99 to $59.99.
I'll say that again. that's TWENTY PERCENT in about 12 years. Less than two percent a year- it's barely tracking the rate of inflation. Hell, it's probably LESS than the rate of inflation. Up until "next gen" the cost of gaming hadn't budged at all, and if you're still gaming on a PS2, GC, or Xbox1 it STILL hasn't.
People, the dollar is tanking. It's currently worth less than Canadian money. Imported goods are skyrocketing in cost, and even basic staples such as gas and food have doubled in cost or more. There's almost no other product you can point at that hasn't had a substantial price increase in the past twelve years, and yet somehow gamers expect the price of games to not move at all in twelve years? Seriously?