Company data breach is like cancer (sorry for going to a dark place), it is not a matter of who, but when. I fault all companies not just Marriott. They do not respect the information we trusted them with if it costs to protect it.
It would surpass my toes and fingers if I was to count the number of Credit Cards, Healthcare Providers, Verizon, banks, Equifax (ironic) a company called Nation Public Data (I believe over 2 billion records) that I have been notified my information was hacked. The companies that have been hacked are so kind to pay for monitoring services for 2 years. The challenge is SS, date of birth, mothers maiden name never changes and much of the other information infrequently changes.
I pay for monitoring my information using Amex credit secure services and a Costco offering that I pay for. I got so many notices of my information on the "Dark Web" that I sometimes feel a flashlight is shining on my information. I froze my credit with all three credit agencies. All reasonable steps. These are reasonable steps to take to try and prevent identity fraud, unless you were a victim of identity fraud. The ease of someone applying for over 50K of credit cards in 48 hours and given bold enough to call the credit card company to change address to get it shipped elsewhere changed that. I added a password protection to my credit cards requiring a password when calling up the credit card company and speaking to someone. 75% of the time they never ask me. I got tied of complaining. I added password protection when speaking to my bank on the phone or doing any face to face at the bank. Lastly, Fidelity has my 401K. Money can only be withdrawn or information changed at a location. I have done neither so I have no clue if it really works.