Built in china cabinets were fairly common in vintage kitchens and not just in luxury homes. I’ve lived in three relatively modest 1920’s apartments that still had them. And, when the kitchen didn’t have them, sometimes the dining room or butler’s pantry did.
The built-in cabinetry in the photo is marvelously intact, but it’s a shame the door pulls were replaced. Though they’re covered in paint, at least the hinges are original.
Some built-in china cabinets undoubtedly went to the landfill when the homeowners remodeled. Fortunately, lots were salvaged as well. I’ve seen them at flea markets, reuse stores, and thrift shops. If you don’t find what you need at any of those, your best bet is an architectural salvage shop.