Though it is right that the chances of occuring big hacks during a high price of bitcoin are very high because they know they will probably get more money in dollars if they hack bitcoin in the current price, but i personally don't think that a hacker has enough patience to wait for months for just bitcoin price to rise so that he can start his hunting, but they just do it whenever they want regardless of the price.
It is very hard for hackers to exist since the bitcoin is very secure and has many advanced security features and passwords measurements, because of how different the baking system from the bitcoin wallets, it is hard for hackers to hack wallets, since they don’t have a constant address, the only way they could hack them is if they hack the user’s pc and even then they still can’t not pass the password system.