Los Angeles (i.e. Hollywood) could be a strategic move given Amazon's massive push in original series and programming via Amazon Studios. Also, shares a coast with Seattle.
They would also have a monopoly on CS grads in the LA area ([0] among the highest number of grads in the country) which is experiencing a serious brain drain of talent to the Bay Area, NYC, and Seattle.
I'm surprised that LA is experiencing such a brain drain, anecdotally, it seemed there were quite a few LA/SD area jobs in last month's job listing.
My gut tells me the job market is worst for junior devs in SoCal. Junior level openings aren't growing nearly as fast as the number of students trying to break into the workforce. A total of 0 of my friends at USC who were CS grads stayed in LA.
Theres several reasons why LA is a good choice. As you mentioned Hollywood and Amazon's push into original content. Amazon is also pushing heavily into gaming, and So Cal is one the best areas for this. Amazon's biggest fulfillment centers is in So Cal. Access to ports along the coast. LA is dumping billions into public infrastructure with the Olympics and measure M. LA has a lot of good schools in the area, USC, UCLA, Cal tech. LA is very forward in terms of govt policy, look at Elon's Boring Company as an example. If Amazon ever wants to get serious about Drone delivery I imagine LA would be perfect for this. On top of the other reasons of its proximity to Seattle and Asia.
El Segundo would probably make the most sense....exact proximity to LAX, friendly business climate, lot's of warehouse space being converted into offices already.
I'm thinking more mid-city/mid-Wilshire area. Still close to Hollywood/WestLA/DTLA but much much cheaper and less dense.
And LAX has good flights to Asia, which is important for sourcing goods.