$10M doesn't go as far as you'd think in the Bay Area or NYC.
Of course there are some who want $100M.
But most are really happy that they most likely don’t ever have to do anything they don’t like.
(And on a serious note - if your parents are both still alive and moving in with you while they have hobbies and self-actualization, you're way ahead of the game)
Utilities are an order of magnitude less than being taxed ~$35k/yr and hardly worth worrying about while discussing eight figures
Maintenance can vary, but all 3 costs you mentioned combined would be 2 orders of magnitude lower annually than that net worth, which seems easily sustainable?