Many of the surviving examples of historic architecture we consider classic today, were ugly or dilapidated mass architecture in their time. Ask someone in 1900 what they thought of a New York tenement or a Sears mail-order home, and they would look at you like you were insane for suggesting those characteristics now command seven-figure premiums.
(What would've been the true beauties of those eras, the mansions, are mostly gone, mostly because they tended to be in high-value areas that would've been redeveloped in later generations because of said high value.)
Surely the opposite effect must also exist - that the historical buildings we see today are the ones that survived because they were considered worth keeping - you wouldn't expect the ugly/shoddily-built ones to survive. However given there are entire streets with attractive historical buildings in many towns and cities I'm not sure either theory explains much - there are virtually no streets I've seen anywhere in the world with almost entirely attractive modern buildings.
Usually it's how hard people fight to keep a building.
Take the NYC tenements. They were substandard housing when they were built, with multigenerational families using a single room on a floor with a single shared bathroom for the floor.
A lot of times, the reason we lost wealthy housing or buildings, is because wealthy tastes and fashions changed, and they no longer cared for outdated buildings, which may have lacked modern electric or water services. Or the wealthy may have moved on from the area entirely; in the mid-19th century when mansions were built around it, Central Park was the edge of NYC, but 100 years later these barons preferred pastoral estates in Long Island, upstate New York or New Jersey, and their old mansions were in the middle of a metropolis.
Poor areas were more likely to not get redeveloped via market forces, because there wasn't money to be made giving poor people the latest and greatest in housing, and on top of that poor people were not going to demand the latest and greatest because they wouldn't be able to afford the rent on that kind of building. And people fight harder for their housing if its redevelopment means getting displaced onto the streets. Gentrification of poor areas in the United States doesn't really get going until the '80s, by which time we already have historic preservation laws.
Obviously there are exceptions to these scenarios but this is one of many sources of why some buildings survive and some do not.
Many of the surviving examples of historic architecture we consider classic today, were ugly or dilapidated mass architecture in their time. Ask someone in 1900 what they thought of a New York tenement or a Sears mail-order home, and they would look at you like you were insane for suggesting those characteristics now command seven-figure premiums.
(What would've been the true beauties of those eras, the mansions, are mostly gone, mostly because they tended to be in high-value areas that would've been redeveloped in later generations because of said high value.)