Museums should permit water bottles

Museums should permit water bottles (maybe with the exception of metal, unclear bottles). One typically spends hours in a museum, and the cafés are overpriced- and often still not allowed within galleries. If you are on a vacation trip, and making a museum stop during your itinerary, who wants to go through the trouble of renting, waiting in line for a locker (if they even provide them) to check in a water bottle.