Maybe if AA had partnerships with more domestic and international carriers for frequent flyer accrual, they could have kept enough market share to make the AUS-SJC route sustainable.
AA had some of that with Reno and Midway in the early 90's, and it did help out for a while on the east and west coast, but some of the unions saw it as illegal outsourcing, so maybe it's contractual now....
Just about every other network and large carrier in the US has reciprocal mileage accrual agreements with other US carriers (i.e. UA & US, CO & DL for the time being, CO and UA in the immediate future, AS with AA, DL and CO).
When some of you are looking at the evils of ATI and alliances, perhaps you need to take another look. Getting ATI or having partnership agreements for mileage can mean all the difference on some of these thinner routes surviving.