The 3rd gen metal-framed pistols are pretty much reserved for LE/Gov orders. Last I heard they were moving production of them to their Houlton plant (which also makes the M41, other .22 pistols and the SW1911 line, in addition to their handcuff line). This move appears to have involved a significant upgrade to the manufacturing capabilities of that plant.
The CHP adopted the newest M4006TSW model (with their own model variations), and if they follow suit with their previous use of the older M4006 they'll probably be using it for another 20 years. I know other agencies which still use new TSW's and have been told of some long time S&W customer agencies which still order older (pre-TSW) models. I handled some new production 3913TSW's received by an agency within the last year, too.
The last time I spoke with a LE field rep, he said the 3rd gen guns might be discontinued all together in another 12-15 years. Obviously, they would like to shift their LE/Gov customer emphasis over to the M&P pistol series. I wouldn't be at all surprised to see some incentives continuing to be offered in this regard, such as offering to replace existing 3rd gen service weapons with M&P's for either little cost or an even exchange.
The 3rd gen armorer classes are still being offered and they're obviously still supporting them with parts (with the exception of some of the older 3rd gen model barrels, some 10mm components, some assorted other older parts, etc).
The market is simply driving the manufacture and sale of plastic framed centerfire service-type pistols which are less costly to manufacture.
The continuing commercial popularity of the 1911-style pistols will continue to drive manufacturing of this model line for some time, I'd think, although its use in LE/Gov circles is still rather small compared to other designs. (LE 1911 armorer classes from the major makers are somewhat harder to find than those for other designs.)
Don't be surprised if even Sig Sauer starts to shift attention from their metal-framed lines to their P250 for LE/Gov sales.
It simply costs more from the manufacturing perspective to produce metal-framed pistols than plastic framed pistols. Having listened to folks from Sig Sauer and S&W discuss what's involved in the way of manufacturing and QC comparing making metal & plastic model lines, it's easy to understand why they're shifting attention to their plastic lines.
Personally, I tend to favor either a nicely made 1911-style SA or a traditional double action pistol (with either a steel or aluminum frame), but the plastic pistols are pretty much riding the crest of the wave of change when it comes to semiauto pistols.
I own half a dozen plastic guns myself, being an assortment of pairs of Glocks, SW99's and M&P's. Having been trained as an armorer for all 3 designs I can see and understand the utility offered by them ... even if I still like my metal-framed SA & TDA guns.
And now we're even seeing the introduction of plastic when it comes to small revolvers ...
