Are you sure? I found the same articles about Philadelphia, but what prompted me to google "broccoli rabe shortage" in the first place was not being able to find it at two grocery stores here in Baltimore that normally would carry it.
Obviously you have a better track to this sort of information than I do, but I can't imagine that in a world with, you know, trucks and stuff, that one city alone would have to go 4-5 weeks without the stuff (as indicated by what I read). The cause is alleged to be droughts in Cali and AZ where the stuff is grown? I can imagine that perhaps closer to the source, where supply chains are more localized, that you might not see as much impact in LA, but I'd think that what impacts Philly, e.g. larger producers with national distribution, would impact most of the rest of the country... which jives with my anecdote.