Scale Models is still active and in business. They supply the 1/8 scale tractors for the PA Farm Toy Show that Outback Toys handles. I've found my best source for them is local farm toy auctions. Finding newer models is a challenge as I've not seen any real online presence from 3rd party dealers that sell new stuff. Implement dealers in my area such a rural Massey Ferguson get in new diecast from Scale Models.

https://riverbottomtoys.com/ They're a newer company focusing on 1/16 attachments for tractors. They have a tractor pulling sled which to my knowledge is the only such example in 1/16. They are pricey but each piece is hand built and welded.

https://smittytoytrucks.com/index.htm Smith-Miller still makes new 1/16 semi trucks on the west coast. Super pricey with some models in the low four figure range. For the adult collector/investor only. I see these sold at local auctions for good money with a mix of older models from the 50s through newer issues.

https://www.mooresfarmtoys.com/ Stretching the term mass market but Moores does offer custom 1/64 scale pieces for ag related purposes. All their custom made product line are made in Ohio.

Precision Engineering produces primarily 1/16 scale 4x4 tractors from the 70s-00s along with some other vintage stuff. I've only seen one person at auction this year and I bid on it and quite after it went for $300+. Company is based in Urbana, Ohio.

There's got to be a few more but right off top of my mind this is what I came up with. SpecCast was still making toys in Iowa up till the late 90s. The latest copyright date from anything MADE IN USA from ERTL that I have is 1995. Their factory in Dyersville might have still produced toys till 1996 before they moved production to Mexico. Scale Models was the only major large scale toy company to keep production of ag related toys in Iowa.

Good question! The only I could think of proved a dead end...after some minutes researching I finally got a good shot to find out they were made in China too...like everything else these days it seems!

Remember when toy cars were made just about everywhere except China, the US, Canada, European countries, and of course Japan don't even seem to produce much in toys anymore, and maybe only some specialized diecast collectibles as mentioned.

The most recent thing I have that's made in America is a 1/64 Penjoy semi truck I ordered from a diecast club I belonged to with their logo on it, I remember it was kind of expensive at $45, and that was 15 20 years ago, so don't know if Penjoy is still around, and not sure if I even still have the truck, as I had a friend sell some stuff back during the recession and forget all what I got rid of.

Spain, Bulgaria and maybe still Brazil...those are the only places left I think that still make their own diecast, even if the Bulgaria and Brazil models are "under *expired* license."

Aren't some Sikus made in Poland?

bottom line...people wanted cheap diecast so the manufacturers went to the cheap places to get it made.

I will put it in another way. The manufacturers wanted to maximize their profits and went to the cheap places to get it done.