Honestly, it's the ideal density IMHO. I get the convenience factors of urban density, but without (most) of the downsides of a high-rise condominium building.
Kids are noisy, they walk hard and jump a lot. You can lecture /punish all you want. That doesn’t change their nature.
For a time we were apologizing to the grouchy old lady living alone below us in a 3 bedroom. Hitting ceiling with broom at every noise. But at a certain point. Look 3 bedrooms are for people with family. I’m not going to force a 2 year to sit still 24 hours a day.
After one absurd ceiling episode we started family jumping exercises for every broom whack.
Never going back to multi-tenant if I can help it.
It’s why I never consider living in townhouses, duplexes, or apartments anymore. I have to not share a wall - otherwise I will definitely hear the neighbor. It’s guaranteed. Even in SFH, I still hear my neighbors - just don’t hear them walking around their house like I would in another type of home.
Duplexes, triplexes and tenements dominate any decent sized city (100K+) in Massachusetts. It’s just what tends to happen when cities were founded 350-400+ years ago.
It's got pros and cons. I think the big issue I observe here is that it doesn't help affordability in any noticeable way. Whenever the single family units are destroyed, they are typically the older / lower end variety first, which had previously been attractive as rentals for lower income people but now they have massive value as teardowns so they can be carved up. Those houses get replaced with high end new construction. So this results in increased real estate value and ultimately a concentration of amenities around these areas that are being "plexed." No affordable housing is built (since this is a southern US city, all low income housing is pushed away from the city core to the exurbs, with long car drive commutes).
Another con is that this town does not have public transportation, and their roads are ill suited for 2-3x the old density. This results in the dreaded "stroads" that have numerous stoplights, carry 5-6 lanes of traffic, and are lined by strip malls as the only connectors.
And finally, when a neighborhood gets "plexed," all the existing foliage is destroyed because it is in the way. So the newly plexed zones are barren with only small shrubs and decorative plants, no trees at all.
I think town home style developments make a lot of sense conceptually. They provide easier access than an apartment building and are much cheaper to build. The density improvements are real, although though not as large as an apartment. I just worry that the way it's being done is rather careless and with little thought for the future, at least in the southern US town I am staying in.
Our love affair with middle-density housing is a bit of a cultural/historical oddity; there really aren't other places in Canada where this is wide-spread norm.