Although Long Beach had been an outstation, all the Douglas prop aircraft built until the end of the 1950s were asembled at Santa Monica. It was only when the jets came the emphasis moved down the coast.
The 717 didn't sell, but that wasn't Boeing's fault. The MD-95 (as it was under McD Douglas) didn't get the orders either. The poor returns were one of the reasons why they got sold to Boeing. McDD had a long history of missing the market (MD-11 trumped by 777, MD-80 used old-fashioned engines). The MD-95/717 was hawked round the world, but very few people wanted what it offered.