Not that you're wrong that JD has a huge following, but over the past 5 decades they have basically gone the way of American auto manufacturers: everyone knows that their products are inferior to the "imports" (which are all made in America anyway), and they survive by brand recognition, big head start establishing a dealer network, and servicing product categories that nobody else does.

Kubota is basically the Toyota to John Deere - they are eating JD's lunch in quality and buyer/owner perception (as well as sales volume) in the "small cars" segment, and is quickly moving up-market. Kubota doesn't sell combines yet, for example, and they are still not outselling JD in anything other than compact tractors, but the people who buy those (myself included) will never go back to JD. Deere has been plagued with quality issues and where they do innovate with some flashy features at times (just like the F-150 does vs the Tundra), they seem to often cause more trouble than they can be worth.

I would say that (depending on the "trade war" of course) Kubota and the "imports" will surpass JD in total units sold some time in the next decade and then start eroding their dominance in the large tractor market in the following decade, if not sooner.