The difference is that a larger, newer chain hotel likely does a better job of providing accessibility and accurately describing it on their app or website. It's not that independent hotels...or B&B's or AirBnB's or whatever...aren't built to code, it's that Marriott.com (as an example) describes exactly
how accessible the hotel is.
Originally Posted by a random Marriott property's Accessibility page
Accessible guest rooms have a 32 inch wide opening
Business center entrance
Fitness center entrance
Hotel has on site accessible self-parking
Main entrance
Meeting spaces
Pathway to registration desk
Pool entrances
Registration desk
Restaurants and lounges
Route to accessible guest rooms is accessible
Self-operating lifts or sloped entry
Service animals allowed for persons with disabilities