Not to detract from your main point, but I don't think Siesta is very common in Mexico and most other Latin American countries. I was born in Cuba, lived there for five years and lived in Mexico for about three or four. I don't know of a single person who regularly slept after noon.
In fact, I had an opportunity to live in Barcelona for three months and while a lot of businesses do close down from noon to three, I got the impression that people were not using that time to sleep, and that the idea of siesta in Catalunya is on the decline.
Ok, I did work for Bolivia for a time, and our Bolivian office closed for siesta, as did our main customer (the La Paz city council).
Same for a more rural area of Mexico (Toluca surroundings), they also did siestas there.
Googling a bit, acording to Time magazine, siesta was struck down in Mexico in 1944, so it's more a myth than reality now I guess (probably subsists in some more rural areas).
My impression was that siesta still persisted in some countries, but that it tends to disappear as they conform to western work hours, and, as the Time article states, it does involve four commutes instead of two, so it's not workable in urban areas (btw, people who siesta still work the same amount of hours, I'm not saying they work less).
Observation: In the Philippines, most parents force their kids to take a siesta. These are taken around 1 or 2 in the afternoon. However, some parents fail to wake their kids up after 3 hours of sleep. In this case, these kids are up till the wee hours of the night, making their sleeping habits more complicated than it should be.
Regarding the article, I guess one should just do what works for them (their body). Some people find it necessary to get 8 hours of sleep, and some are okay with six.
