FIH, not EVERYONE who owns/rents a single family home wants to live “interspersed” with multi-family dwellings. The sole reason for buying or renting on a SFR-only area is to have more privacy. Newer multi-family dwellings built on infill on the same block as SFRs (ex: North Park SD) drag down the value of those long-existing SFRs by adding parking congestion and even dumpsters in plain view on what were once SFR-only streets. In addition, there are more stereos and radios blaring and more people crammed onto that street with frequent domestic violence calls and the like as well as the constant moving trucks of a transient population.
I would not buy an SFR on such a street … even for investment purposes. I would only buy a SFR on a street which was zoned single-family only and would prefer the entire subdivision be zoned single-family only.
SFR zoning and multifamily zoning should be separate as it is in most urban and suburban areas of CA (SF, among other locales, excepted). The two types of areas attract completely different kinds of would-be residents. Without its heavy zoning restrictions, CA RE would not be worth anywhere near what it is worth today.
You brought up Houston, TX. Compare it (with little or no zoning) to SD and you will find its homes are worth 1/4 to 1/10 of a comparable home in coastal CA counties. There are very good reasons for this.
The way builders are able to offer privacy to new SFR homebuyers in Harris Co, TX and other TX metros is through building a walled and often gated community which has CC&R’s (and HOA dues). Such communities are often built around a manmade lake which belongs to the HOA and could literally be considered “islands unto themselves.” It is only in these (CC&R) SFR communities where you DON’T see RVs, boats, tractors and trailers (and tractor-trailers) parked out in front of SFRs. Quite often, the CC&R community-dweller in TX metros drives outside the wall of his/her subdivision and is immediately thrust onto a wide thoroughfare with a hodgepodge of auto-body shops, tool and die shops, dive bars, no-tell motels and/or tractors and rusty camper shells parked in front of SFRs situated on acreages. The non-HOA communities in or surrounding Houston are full of everything, including sorry-looking outbuildings “parked” on residential property, space-permitting, of course.
Strict zoning laws serve their purpose and I am very appreciative that CA coastal counties (and even CA as a whole) has had them in place for many decades (in comparison with many other parts of the country).