Till date I haven't been affected by any of the exchange hacking incident although I have used almost all the exchange that have been hacked at one point in time. The secret is already highlighted in the OP above and sang everyday by the community but my individuals seems to ignore that advice. (Not your key, not your coin). Exchanges should only be used for trading & not for holding your assets.

As for a solution, I don't think there's any currently, the only way to minimize the impact is by having a set aside fund to cover up any damages when it occurs just as Binance did. Also a weekly audit of the exchange to search for flaw which hacker can take advantage of might also help. The thing is, all centralized system (exchanges) are liable to hack & if your decentralized exchange gets hacked then it was not decentralized enough unless it has to do with phishing.