After "What is your GPA & test scores"

That's a tough one.  

First of all, hang in there.  Sometimes a kid is 3  more pegs down the list and it takes a while before coaches know that they have not landed their top prospects. During my son's rising Senior summer, coaches started popping out of the woodwork in August and September; some were guys who had gone silent, while some we had never talked to before. Next, don't waste any more time or energy worrying about support from travel or HS coaches; that doesn't sound like the issue and it won't help. As for sending more emails, yes, if  your son wants to play in college he should keep them up, though not bombard anyone, just to keep in touch. If he wants to make sure they are read, get a service like https://mailtrack.io that will tell you if emails are opened. (get 3 months of the pro service, so it's not obvious).  As for more Showcases, sure, if you can afford it and there are more you can get to, why not? For sure do the AZ Senior Fall Classic + High Academic tryout.  Finally, have a Plan B.  Is playing baseball really, really important to your son? If so, you're lucky you're in CA. Your son can go to a great Juco, save you a bunch of money,  play baseball, and have a guaranteed spot at a UC if he does well in class. Or he may develop further and move on to play at any number of D1, D2, D3 and NAIA schools. If baseball is #2, then at some point soon it will be time to start thinking about where he wants to apply without baseball, or maybe with club baseball.

Just my opinion of course.  Good luck to your son.

My son texted all of the key coaches he was talking to after every game of his junior year with what he had done in the game, next game he was slated to pitch (he was primarily recruited as  a PO, although at our high school he also played third). He sent updates to schools that were interested and to schools that he thought should have been interested.  Eventually, the school he is now attending started sending coaches to his game and then signed him.

I think almost every kid who wants to play college baseball can — if you're willing to accept the trade off. Maybe you have to give up a high quality academic school or go to a D3 when you're a D1 student. And maybe you find out baseball isn't as important as you once thought.

Those are decisions only you (or your son) can make.

Agree with what JCG says. Many HA D3 coaches are in the last phase of watching showcases (going on this week), before they start inviting players on visits. They have a list, and they are trying to figure out all the pieces. Hang in there is the right advice, it will all start moving again, and might keep moving until November or into the spring.

Is he wanting to stay on the west coast? There are many HA D3 schools with baseball in the midwest and east, and some of them offer large academic scholarships for students with very high GPAs and test scores.

Also, you have to figure what sort of mix of academics and baseball your son wants, and what the baseball opportunity means.  I know of various players who didn't play every year of HS, or didn't start varsity, who went to winter camps at D3s, and they recruited them.  Not super-competitive D3s, but very respectable colleges, and ones that would give a lot of academic money to a high GPA/SAT student, that might even be better than being at a super-prestigious school.  But then, the baseball team rosters list over 45 players, so being "on the team" presumably means "having a chance to play" (true at every level).  If you look nationally, there are all sorts of opportunities of that sort.