Seriously, if you check out where some of the top american aerospace achievements happened, AV is in there. What made NASA, the Air Force, and companies all go "Yeah, that seems like a good place for testing and building."
Four letters: KEDW
Edwards Air Force Base is located in the Antelope Valley and was founded in 1933 as Muroc Bombing and Gunnery Range. The Rogers Dry Lakebed was viewed by then Lt. Col Henry "Hap" Arnold as a natural aerodrome - it flat smooth surface and all-year-round good weather meant it was ideal for air operations.
During WW2, this became Muroc Army Air Base. In addition to the fact that Wright Field (now Wright-Patterson AFB in Dayton, Ohio) was at its limit in terms of air operations due to the frentic pace of war operations, the Army Air Force wanted a place to test new secret aircraft for the war effort: the XP-59, the US's first turbojet aircraft. The XP-80, which would become the P-80/F-80 Shooting Star, would soon follow.
Again, the good weather that exists all year-round there for flying, the remote location ideal for security/secrecy, and the gigantic flat dry lakebed made it ideal for air operations and flight testing.
At the end of the war, and with the arrival of the jet age, the long runways at KEDW were extended and with the dry lakebed an ideal overrun/extension of the runways for experimental aircraft, all sorts of craft were tested here, such as the X-1, X-15, etc. In 1949, Muroc Air Force Base was renamed to Edwards Air Force Base in honor of Capt. Glen Edwards, test pilot who died in a crash of the YB-49 Flying Wing, the predecessor of the B-2.
In 1951, the Air Force finally moved their Test Pilot School and Air Force Flight Test Center to Edwards Air Force Base. In response, Air Force Palmdale Plant 42 was opened in 1952, sharing the runway complex with Palmdale Airport and contractors like Boeing, Lockheed, Northrop etc. - who already had a huge presence in Southern California - put factories/depots/plants there to operate test aircraft near Edwards.
To this day, with the huge vast areas of empty uninhabited desert nearby, great weather, lots of restricted airspace/MOAs (military operating areas) available, tons of experimental flight test operations continue in this area (and relatively nearby, the Navy's Naval Air Weapons Station China Lake does a lot of flight testing as well for similar reasons).
You can read more about it here, at what's probably the most official source available:
Edward's Air Force Base History Page - http://www.edwards.af.mil/library/factsheets/factsheet.asp?id=10346