I have a
BX2350, and I'm one of those people who bought it as a bigger lawnmower with fancy attachments - I mow a bit less than an acre. According to Messicks they sell more BXs than any other model, and my view is that people buy a BX because they have a property just big enough to have a tractor. But if they move house they may not need it any more, and the new owner may not be interested in a tractor. So they probably turn over quite a bit. In our part of the world whilst they are for sale a lot, they're very rarely cheap - people are paying most of new price for second hand machines. That says to me that it's not because the machines are too small or not useful, there's just a lot of them around.
I'm in the market for a
B2601. My
BX2350 when I bought it was very banged up - I bought it cheap to see if I really had use for a tractor. Turns out I do - between running a
chipper, moving things with the bucket, lifting things with the forks, quite a bit of mowing and helping out neighbours, I'm probably on it every weekend. So I can justify a newer tractor (probably brand new), and if I'm getting a new tractor I'm going a little bigger. I still only have 1 acre, so a
B2601 is really all I need (even that I don't really need), but it'll make me happy to have a tractor that someone else didn't wreck before I got it.
I do agree that at the very small end of the market - BX and small B - for many people it's a toy as much as a tool. I could do everything I do with a less expensive machine or a ride-on, or with a hand shovel and wheelbarrow, or by taking my tree trimmings to the tip. But I enjoy my tractor, and people I know have far less practical/useful toys than mine - I don't have expensive cars, I don't have endless sports equipment. I think that does play into the features that Kubota put on these smaller tractors - they're quite feature rich and "deluxe" - reflecting that the buyers are generally people who are buying them because it makes them happy, not buying a stripped down economy machine to do a job. The small L is the first tractor in that economy category - and it's at a size where you're starting to do more real work with it than you are with the BX and small B.
To be clear (because people can get the wrong impression), I'm not in any way saying a BX or a small B isn't a real tractor. I do a lot of real work with mine, and I get far more done in an hour than I would by hand. But the reality in this size class is that I _could_ do most of what it does by hand if I really tried. Whereas getting up into an L class machine I think you simply couldn't do by hand the work it does, or at least not in any realistic amount of time.