Because they can create value adds such as club houses, golf courses, pools, entry gates, etc that boost the perceived value of each home significantly. 

You get your buddies together with some beer and start pouring concrete for the kind of big shop/garage you're talking about, maybe digging a trench through your backyard to bury a 16-gauge extension cord spliced into your duplex's panel, oh Mama, you're going to be in for a very ugly surprise. 

My personal price point is getting difficult to find and purchase, so we will pool our resources and look at higher price points, while still looking at the "cash flow" method. 

For all of them... what are the age of the systems (roof, a/c, pool equipment, water heater etc.

Having lived in the Phoenix area for over 13 years, I can assure you that a backyard pup tent has a higher tax rate than $10.

I personally think the greatest advantage of not investing in someones own backyard is being forced to network and build systems.

If the property has a pool there is added risk.

Yes, having the Pacific Ocean in my backyard is a good thing :)

Same with pools, equestrian facilities, and of course, proximity to great schools, shopping, restaurants, etc.After the physical items comes the paperwork stuff like watching out for very long DOMs ( days on market) and sudden rise in supply or drop in demand.

Welcome Tony,I am local to Southern California, this market is our backyard, if you would like to talk a bit please contact me!