Think the main problem was the jump in price from 8bit machines. Software companies were under the illusion that because 16bit machines were more expensive, then people must be able to afford to pay more for the games.
Most prestige 8 bit titles were £14.99 or less, Amiga traditionally was £25.99.
Once software companies had written their game engines, not a lot was needed to tweak them into becoming different games.
Piracy was always going to happen no matter what the price, but £25 for a game was a lot of money for me. And I bought what I liked to play, but how fucked off would you feel to buy a game, and then complete it the day after you got it?