Accurate SYW & AmRev artillery; scarce as hen's teeth?

Why is it that in war-gaming, and for that matter at our US National and State Parks, we can not find accurate models of SYW-era artillery pieces, either in the "28mm world," or in "1:1 scale?"  Look close and one sees that we are usually treated to something, a) remotely "European," and b) post-1765 (or even 1776).  For example, these pieces in the next two pictures are found within the American "lines" at the Saratoga battlefield.

  

If my memory has served me -- from the too-hasty stop at Saratoga this last July -- these small guns on red-painted carriages are supposed to be pièces de 4 courte à la Suédoise ("Swedish" 4-pounders) as used in American service, not guns of the système Gribeauval.  France did provide some "Swedish" 4-pounders to the Americans, so that the guns did serve in the American Artillery in the AmRev is not wrong   The question that needs some research is, were any such guns present at Saratoga?  Especially since, as most school children over age 40 know, and sadly most under age 40 do NOT know (given what our schools teach today), the bulk of France's support to the AmRev came only AFTER the Battle of Saratoga.

French guns in American service aside for now, as National Park tourists or as war-gamers were often sluffed off with post-1776 British artillery pieces, as if, "that's good enough for you lot!"  The next three pictures show a British 6-pounder found in the Balcares Redoubt at Saratoga.

This gun, as I found it this last summer in the Balcares Redoubt at Saratoga, is a good example of an oft-found reconstruction at US parks; a "British Light 6-pounder Gun, 1776," as found in John Muller's Treatise of Artillery (London, 1780 edition), or C. W. Rudyerd's Course of Artillery (1793).  Such guns are not out of place on battlefields of the AmRev, but its not clear that such specific gun-types were in fact those used AT any one specific battlefield ON a specific day!!  In fact, it seems quite logical that at least through the first years of the war, some if not all the British guns dragged through New York, New Jersey, and then to Philadelphia, were based on the earlier "prescriptions" for building them found in Muller's Treatise of Artillery (London, 1756; or even the 1768 edition).

When it comes to the Seven Years War, I have to admit, I have only been to a few "battlefields" in the US ostensibly focused on the F&IW (the SYW in America).  Today, most are National or State parks, and to me anyway their staffs seem desperate to find a way to explain why they have post-1776 guns and carriages in their parks (if they even bother to explain).  For the British, "proper" guns would be those based on the system in place from the 1740s, and the then-recently improved "light" guns being introduced, as described in John Muller's Treatise of Artillery (London, 1756).  For the French, such guns should be ones based on le système Vallière.  A good explanation of the British system in the SYW is sadly lacking (and war-games figure manufacturers desperately need access to one, as do Park Serivce Curators!).  A very good and accessible explanation of the Vallière System can be found at Christian Rogge's excellent blog @ http://crogges7ywarmies.blogspot.com.

Most disturbingly for those of us who are not just tourists at National Parks, but are war-gamers, when it comes to the SYW, the average war-games manufacturer pawns off on us the "British Light 6-pounder Gun, 1776," and guns of the French système Gribeauval.

Its time to protest!!!