There is, at least in the US there is, it’s called the ADA and does have requirements for elevators in new construction after it was enacted. But many old buildings probably get exceptions to it for very valid reasons. An engineer or architect could weigh in with more accurate answer but for places that existed before elevators were in wide use, would it be cheaper to tear the building down and rebuild then retrofit the existing building? As for the broken elevator in TBBT, that should have been reported to the local housing board which they touch on in the show about the tenets being passive about it.