Grammar Textbook Issues

I was in the School of Education department today when I noticed some language arts textbooks on the free book table.  So, of course, I stopped to look at them for just a minute.  I found them inadequate, woefully so.  I was reminded that one of my goals in life is to remake the primary school grammar textbooks so that they reflect all of the great syntax research that's been done in the last 50 years.  This, I feel, is a noble goal and I would like to explain why.

From what I can tell, the way we teach English grammar to elementary schoolers hasn't changed since I was in elementary school (I checked the dates on those textbooks in the school of ed.  and they were recently published).  I suspect it hasn't changed for much longer than that.  Now, to make an analogy, the modern science of molecular biology has its roots in the 1950s with the discovery of DNA structure.  A responsible school board would never choose a science textbook meant to cover biology that didn't, in some way, address the role of DNA.  I remember making a model of a cell in 5th grade, complete with DNA strands in the nucleus.  Yet, these discoveries are relatively recent.

To contrast, Chomsky's revolutionary book on syntax, Syntactic Structures, came out around the same time.  I have yet to see the impact of these discoveries on the grammar textbooks.

Here is an example of how far behind the textbooks are:

Most grammar textbooks would have students diagram a sentence like this:

The cat slept on the carpet.

A syntactician would diagram the sentence at least like this:

The cat slept on the carpet.

If not like this:

The cat slept on the carpet.

Okay, the second one might be a bit complex for grade school students, but the first syntax tree makes the point.  Using this method shows how the phrases work together in ways that the traditional sentence diagram doesn't.  The phrase structure is more transparent in this type of diagram.  Why aren't we teaching this way?  Why are we holding students back?

P.S. I made these trees from memory.  If any of my lingistics friends finds a mistake (especially with the second tree) please let me know so I can fix it.