The resolution on the Neo is just bandwidth, but the number of displays is actually the consequence of a pretty radical design tradeoff from Apple.

GPUs generally follow a philosophy of dumb display controller + GPU handles everything centrally, which means that you can just stick on more display controllers at negligible silicon cost and have enough to blanket all your video output ports, and the only cost is generally higher idle power usage, and especially higher idle power usage if you use many displays.

Apple's design is generally that the display controller for each display should have its own highly power-efficient mini-GPU embedded, so that the main GPU can be power-gated out of existence if you're not running Blender. This gets you huge battery life savings during light usage, and even moreso when using many displays with a controller for each display, but the catch is that the display controller that you need one of per display is now the size of an 8-wide out-of-order CPU core on the die, and very much non-negligible from a cost perspective.

It's a design decision that clearly comes from a perspective of wanting to buy battery life for money, and it makes perfect sense on a phone-originated architecture. It's arguably also the superior tradeoff for a laptop, though you do have to accept that many-displays support is restricted to higher-end chip models. You'd never see something like it in a desktop-originated architecture though, because the tradeoff makes little sense on the desktop.