- Land is expensive and not particularly abundant. Mid-Wilshire is relatively cheap has great proximity to everything (airport, downtown, west LA, Hollywood) if Amazon is willing to invest in the gentrification of the area.

- Labor cost is within 10% of Bay/Seattle/NYC

- Mass transit is currently effectively non-existent.

- One of the highest taxed cities in the nation.

On the plus side, there's:

+ A very well connected international airport

+ A lot of top tier universities nearby (CalTech, UCLA, USC, UCSB, UCSD, UCI, Pepperdine); any one of which can single handedly supply a workforce comparable to the other candidate cities.

It's a lot easier moving people and airplanes to the other cities than it is creating cheap well connected land in LA.