Los Angeles has more wealth, more access to rescue facilities and has structures built to withstand quakes. International aid is starting to arrive but even that takes time. Assessments have to be made of exactly what is needed, where it's needed, and more importantly, how to get it there. Access roads to the region are hard-hit and clogged with traffic. Bringing a convoy of aid vehicles in over them is frustratingly time consuming but the first trickle of outside help appears to be making it in.
Local airports are still largely unusable.
This region is not wealthy. There is not a lot of money available and relatively little rescue equipment. For those reasons, the timeline for cleaning up and starting again is going to be lengthy. Meanwhile, at the very human level, this earthquake has of course been devastating. That said, people who are watching as bulldozers clear crumbling buildings are somewhat fatalistic.