It came about when building materials we're not in abundance. The local traditions were followed. The Santa Fe Styles were and adaptation of Native American Pueblos. Adobe mud blocks were used, cheap and plentiful, especially with cheap Mexican migrant labor. Just add stucco.
A bit of territorial style changed the boxy look. The use of natural lines, earthy, appeals to me and the creativity of it. My house, a strawbale, looking like old time adobe sold at a premium because of the thick walls and these rounded and styled standards. It is desirable to those that can afford the hand constructed look. In Tucson, even the tract houses have attempted to incorporate many of these elements. It is primitive. Primate works very well, has for millennia.
Kind of a waddle and dab-ish thing, hacienda in the country. Stop by and I'll show you some examples of these older places that go for ridiculous prices.
Jbee