I never said they were. I only said that they were built to last and that they were infinitely more aesthetically pleasing because we actually gave a damn about these things as a society. Now we don't.
Old buildings can be upgraded (I should know, I live in one, and have both functional pipes, insulation, heating, and Wi-Fi). So let's upgrade them, and let's ALSO ensure that whatever we build today includes not only modern amenities, but are also objects we can be proud of leaving as a legacy to future generations. Just like our ancestors did for literally millennia.
No, the buildings that survived are generally more aesthetically pleasing, most old buildings where shacks. Walk around an old plantation for example and the slaves quarters didn’t survive. Search around for some original outhouses and you realize what survived isn’t simply representative of what was built.
Growing up in a 200+ year old building you find a lot of architectural designs and modifications that don’t fit with modern usage. Pre AC maximizing summer cooling involved maximizing airflow where now we want maximum insulation. Before central heating we wanted chimney’s everywhere. And before wood stoves we wanted giant fireplaces everywhere. Even central heating has gone through several iterations, many different radiator designs for steam/water, central air, and now a zigzag of pipes underfloor.
Very old buildings may look nice, but they aren’t inherently better.