I have lived in three comparatively small 1920’s apartments that had them. And, once the kitchen did not have them, on occasion the dining room or butler’s pantry failed.
The built-in cabinetry in the photograph is marvelously intact, but it is a shame that the door pulls were substituted. Although they’re coated in paint, at the hinges are all original.
Many built-in china cabinets definitely moved to the landfill once the homeowners remodeled. Luckily, lots were also uninstalled also. I have seen them in flea markets, grocery shops, and thrift stores. If you do not find what you want at any of these, your very best choice is the architectural salvage shop.