Because they are proven, uncomplicated and cost less are just a couple of reasons that come to mind. I also can not see what all the fuss is about hitching them up. I have no issue with hitching mine up, sure it may take slightly longer than a drop in or on style hitch but at the end of the day I am in no hurry when hitching up. It also does not matter what hitch you use you still have to reverse your car up to the camper and line it up
I totally agree. Mine has done over 35 thousand k's since i bought it and it was second hand. I back up to it and the missus guides me, quite often she has the pin in it before I get out. The new wave of hitches are in response to a market, not a problem. They invent them then tell you why the one your using is so bad. Just like mobile phones, how many people are about to race out and replace their iphone 3's with the 4's because the old ones are so bad....
Also, drop on ones like the do35 are comparatively weak up compared to down. So if you drag your drawbar allot on trails you could damage the retention mechanism.
How may of you know of an actual hitch failure? Even a ball failure? Anyway, even if the hitch is rated to 10t its mounted on a bit of plate that is welded to 3mm rhs quite often by some bloke in his back yard with GP rods.
The good old poly block even insulates a little vibration between the trailer and you and you can get them in override if that’s your thing.
So I would save your money and spend it on fuel for your next trip.