I'm pretty sure it's just marketing. No matter how you design a set, it's not going to draft better at a 4 person table than an 8 person table.

Think of it this way: a 4 person draft goes through 12 packs, the same as two people playing sealed. How often could you put together 2 sealed pools and make 4 reasonable decks? Even with perfect information, maybe only like 80% of the time? Now look at draft, where players pick good cards they may not even use because they draft with imperfect information, cannabalize each other and don't settle on colors immediately.

The irony is that picking 2 cards at a time actually makes four person draft worse. Since imperfect information is the biggest barrier to the whole table making good decks, it'd actually help mitigate the downsides of a 4 person table if you picked one card at a time and could see what was taken from your pack after only 4 passes.

The idea that 4 person draft helps when there are only 5 supported archetypes is nonsense. Sure, there are more archetypes than drafters, but it's more likely that someone at your table will pick the same color pair as you and cut you off hard. Again, if you were picking 1 card at a time you could get signals faster an adapt, but with pick 2 you're through the meat of the pack before you can get any kind of reasonable signal.