It completely depends on the neighborhood. If people are buying just for location, the value is only in the land anyway. Which means you will see more and more new homes. The new homes do not want to be next to the old homes, generally.
Drive through the close in neighborhoods yourself, and you will see how quickly they are turning from old to new. A small percentage of these are kind of what OP describes. They are new homes built on the old footprint. The reason for this is usually because it is easier to build on a basement that already exists. It also allows the builder to keep the current position of the house, without sacrificing any space.
In addition, the builder can easily get a variance for the new construction (built onto the old basement) for the frontage to extend by about 10 feet or so. Again, if you drive through many close in neighborhoods often enough, you will see this happening.
Do NOT expect the old homes to be in favor of the new homes. Don't you think if the old home homeowners could afford the new homes, they would?
My friends have what OP describes. They are not necessarily "flips", as they are very high end in the pricier neighborhoods, where there is more space in between houses.
Generally, when people spend a certain amount on a home, they have a reasonable expectation to be amongst the MYOB types.