I wish there was an easy answer to this. Unfortunately, until companies are protecting the application accessing their servers, the “site” and the user’s interaction can’t truly be protected. The best things that consumers can do now is:
Be educated - read and learn about sites and companies that have been breached or found vulnerable.
Vote with your time and money. Be much more cautious about transacting or interacting with online businesses that have had a breach or loss. Let them know that not truly securing your interaction with them is not acceptable.
Be prepared to have your data lost or stolen. This is an unfortunate reality today. Don’t transact online with debit cards or uninsured payment methods, secure all online accounts with different credentials and leverage a reputable password manager to use unique and complicated passwords, make up false answers to security questions (and store those securely), and where possible, check the credit reporting agencies often and/or freeze your credit so new accounts cannot be fraudulently opened up against you.