This is a great subject, and unfortunately one of the most complicated in a very complicated game.
Let me begin with one undeniable truth. Parental authority can be delegated, but not parental responsibility. IOW, a parent has the final say about certain things when it comes to their children. I know coaches don't like to admit that, but they aren't the ones sitting in the hospital room after surgery or paying the hospital bills! Unfortunately, for many reasons in sports, parents will not intercede even when they believe their child is in harm's way.
Next, everyone in Ca who really feels this subject is a serious one, should thank their lucky stars! The NFHS rules require each state assn develop some kind of pitching limitations. Some years back I compiled a pretty comprehensive list of all the limits from all the states. See link.
To say the least, Ca has the most strict limits in the nation! Even if you only scan through that list, you'll see that some other states have nothing more than jokes for limits. See Louisiana and Texas for proof.
Unfortunately, pitch limits by innings is pretty stupid when you look at it closely. Why? Because an inning can be of any length from 3 pitches to literally 300. Sadly though, only North Dakota and Vermont to my knowledge have gone away from inning limits and gone to pitch count limits. Why? Because there's so much opposition to pitch counts, both unreasonable and reasonable.
Its patently unreasonable to fight to keep inning limits when an inning can vary so greatly. Pitch count limits are not all perfect, but they are far superior to inning limits. Its unfortunate, but the truth is, no limitation is gonna work equally well for every pitcher, and therein lies the main problem with pitch count limits.
If a coach pushes the envelope, no matter what the limitations, a lot of pitchers are gonna be injured. But the only way to really mitigate that is sadly beyond the control of most coaches. The mitigation that would work the best, is to have more than 1 or 2 good pitchers to carry the load. But not many HS coaches have the ability to really develop pitchers. They don't generally have the time or knowledge it takes to do that.
One of the best arguments against pitch counts is that not all pitches are equal, but they're counted equally. I'm not talking about the argument against breaking pitches. That's a separate topic all of its own. I'm talking about pressure. In recent years there's been more and more talk about the pressure of a pitch. By pressure I mean mental pressure. Here's an example. There's a lot less pressure on a pitcher who's throwing a pitch in the top of the last inning with 2 outs and a 9 run lead, and a pitcher who's team is tied in the bottom of the last inning with the bases loaded, no outs, and the kid who's just been drafted in the 1st round because of his hitting.
So while the pitch is still only 1 pitch, it wears on the pitcher in different ways. Another example would be one pitcher having thrown 90 pitches in 6 innings with only a few base runners, and another pitcher having thrown 90 pitches in 4 innings, with almost every pitch being thrown with runners on.
I happen to be a nut on this stuff so I actually track it, along with lots of other stuff, so although I'm a staunch supporter of pitch count limitations as opposed to inning limitations, I can certainly understand how difficult it is to really put a value on each pitch.
In the end, it would be nice if there were some national authority looking into how to deal with this issue and govern it, but the truth is, there isn't. Because of that, we've all got to accept that bad things are gonna happen to pitchers, and hope coaches don't do things that make it worse.
http://www.infosports.com/scorekeeper/images/pitlimitsa.pdf
