What did the other factories try to steal from MrWilly Wonka an why Charlie and the Chocolate Factory?

Answer 1

"Charlie and the Chocolate Factory" is based on a true story: When Roald Dahl was a child, the two biggest candy makers in England used to send spies into each others' factories to steal secrets.

In the book and the movies made from it, the other candy makers knew Wonka's was the leader in creating delicious new candies made in new ways, such as Wonka's ice cream that wouldn't ever melt. They wanted to sell these candies without spending the time and money to invent them, so they had spies steal the recipes.