Kenny - it's an interesting topic.
Like you said, there's SO many BX threads. I have a BX too.
I think skeets said you guys with the bigger machines may have been around tractors a long time. It's what you do for a living or a very serious hobby to justify the $$ for a big tractor.
I grew up a farm boy, and still have a whopping 32hp tractor, but it's 7,000lb and 60+ years old. Even that old-timer can still lift, push and pull some serious stuff.
Years before I bought my BX2360, I took my Dad to a local Kubota dealer to look at BX's. He thought they were the bee's knees, and all he knew were "real" farm tractors. Like dlsmith said, I looked at them for years, and finally bought one in 2013.
What I found was that when I had a JD Garden tractor (1992 JD425 with mower, blower and blade), for a few $$ more than another JD replacement, I could get diesel, double the weight, a loader and 3PH with a Kubota. We all know what those options add for versatility.
Early on, I wished I had looked just a little bigger Kubota (B series), because maybe I thought it could do more. That said, I love my BX. Lately I've thought if a change were made, it would be to add a larger loader tractor, and keep the BX for mowing and snowblowing.
In this day-and-age, there's guys and gals that are looking for a "Swiss Army Knife" tractor for their rural or suburban properties. They need something powerful for it's size, versatile over all seasons, not too big, and easy to service and to store.
Thus, welcome the popularity of the BX. I have no idea the number of units Kubota sells by series, but I'd guess BX and B are top of the list.
Again, getting back to skeets' remark, some/many of those BX owners' are new to tractors. As such, they look for help where they can get it, and find OTT...
Those guys and gals that buy an M series for their working farm probably don't as much help from an on-line forum.
I might be way off, but it's just my take on it. Again, interesting topic!