Maybe I'd be a bit more optimistic if someone could explain a realistic economic scenario for how we're going to transition into our utopian abundant future without a depression or a revolution.
The incentives are, how you say, aligned.
The deeper issue I see is the psychological crisis for a species who believes it doesn't deserve to live if it isn't performing economically valuable activity, entering a world where it is unprofitable for it to be employed. (If I were the AI, I'd come up with some kind of fake jobs to keep the humans sane.)
UBI funding doesn't come from thin air, every job has to pay for itself, even if it's just UBI. Mixed costing wont hold up because every market, every company, every worker acts on it's own. So companies must pay extra plus UBI, which will only lower prices if the overall salary gets lower at the end of the day.
In my world UBI should be an psychological tool that empowers people. The way UBI is usually discussed, it's a magical solution to a very hard, incomprehensible problem and the simplicity of it just throws 70% of humanity under the bus. It's literally the same we have now, the only difference is that now everyone can claim that everything is fair because of UBI.
Gen Z would likely have a very different opinion if their basic living necessities were available to them.
One aspect almost certainly has to be data centers being run as utilities. That forces transparency, resists monopolization and gives public commissions a say in e.g. expansion.
We need to let the AI as a service businesses fail.