The topic of UB is continuing to create controversy as the number of non-Magic IP products explodes. The Professor put out a recent video on the topic predicting a future Universes Within product to make up for all the unique UB cards being added to the mix, but looks like MaRo has quickly shut that idea down.
What are players who don't like UB supposed to do when there are no Magic versions of those cards? This is now just reality.
They're intending for Magic to go the way of Lego. A bunch of different IPs in the mix and you'll only engage with the sets you choose. If that's only UW sets, they're ok with that. For every one person that says they're going to quit because of UB cards/sets, there's likely 3-5 people that are picking up the game for the same reason.
The unfortunate side of this is that you don't get left out of competitive Lego if you decide to not engage with a set.
It's a business first, so someone has done the math to make sure that this kind of risk is worth it. Starting with Secret Lairs (Walking Dead) was a genius way to test the idea. Same goes for everything else they've done recently, new foil types, serialized cards, etc. They wouldn't do that stuff if it didn't make them money.
I'm not advocating in favor of this kind of behavior, but it's the reality of how product development works. You ship, test, iterate and ship. As long as they project growth, even if it's at the expense of their most enfranchised players, they'll continue to do whatever is working. You just have to decide whether it's an environment you want to participate in.