Exchanges should put strong security measures in place, such as cold storage for individual funds, regular security examinations, and powerful authentication protocols.
Exchanges move customer funds, deposits from hot wallets to cold wallets. They do that to secure their exchange treasury and first they care about their exchange, not their customers. If they are good exchanges, customer funds will be safe. However, if they are scam exchanges, they will run with coins in cold wallets.
Cold storage for individual funds? will every customer willing to give $100 for the exchange? nah, the reason of why most of people use centralized exchange is they don't want to lose any money, if they can't afford to lose for paying more in Bitcoin fee, how it's possible they willing to spend $100?
I am confusing.
People can set up their cold wallets with non custodial wallet, free. Buying a wallet like hardware wallet cost you but it is not related to Bitcoin fee. They don't pay Bitcoin fee to buy a hardware wallet or a cold wallet.
Creating a cold storage wallet in Electrum