I think this is an unfair characterization of people that keep large sums on exchanges. It’s not unreasonable to trust a company worth billions to hold your funds. Some might even argue an exchange is safer than a hardware wallet in the sense that if you physically lose the wallet, or completely forget the password, you’re SOL.
No one expects a multi-billion dollar exchange to vaporize over night. All that has changed this week. However, I don’t think it will have much impact on people storing their crypto off exchange. What I do expect is that reputable exchanges will start being more open about customer funds, and audits of those funds.