The chance of this happening is 99% in the next 2 years. If you doubt it, ask a computer security expert.
https://en.wikipedia.org/wiki/Attack_surface"
Banks have a lot of money in "hot wallet" too. It's not different, and they don't get hacked Moreover with LN I'm pretty sure you can hide behind tor
What's the difference ? There is a lot of cash inside "banks" (or ATM or whatever) that you can just steal if you hack them. If we use crypto it won't be different, we won't have hacks