Completely agree. They are geared for the corporations, research, universities, government, and institutions markets, where those purchases are long term, and often for revenue-generating and mission-critical tasks. If something fails, you can always count on them being there to support you to get you going, so your highly compensated engineers are not sitting around due to broken equipments. On top of it, you have complete asset management, life-cycle transition planning, and extended service/calibration services. The portal tells you everything you own, when was it last calibrated, all the calibrated certificates, when is calibrated due, recall/services notes, repair history, contract expiration reminder, etc... And when something breaks, you can have their service come to your lab to pick up the equipment and carry it away in their specialized equipment van without having to worry about how to pack it and shipping damage. Hence the support model is at a different league with the Keysight (I presume true with some other A-Brands), and the price reflects it. But for those clients, price is just one of many factors that go into a buying decision.
For the B-Brand, their support is more akin to those of consumer electronics. And for the C-Brand, it is more like buying something off e-Bay, you may be able to exchange it, but there may not be any warranty.
For the hobbyist market, budget is often tighter. So the premium may not make sense to some, and the B or C brands may make more sense. Hence the beauty of the free market, we can all pick what we like and what we are willing to pay, there is no single right answer.