Rather than discouraging people not to invest, I think the larger concern is the further entrenchment of a three class system.

You'll have your capitalists, those that own the assets and robots and land. Then you'll have some amount of humanity lucky enough to get one of the jobs not automated. Finally you'll have those existing purely on UBI.

The economy will shift towards catering almost exclusively to the first two groups and anyone on UBI will be seen as a useless parasite. There won't be any efforts to price goods and services for this group beyond the bare minimum because they have very little buying power and zero earning power.

I think we've seen time and time again that the rich are more than happy owning a small pie rather than putting in the work to build something bigger, even if that would result in larger profits long term. It's going to be easier to just shrink the economy to those that still have jobs than it will be to make everyone have more equitable buying power.

UBI will probably happen and probably get paid, because it will help prevent revolts and unrest, but that is a cost center to the rich. You minimize cost centers as much as possible. It's a subscription they pay to the masses to reduce risk and that's it.

UBI will probably come, but much like AI, we're probably not going to be happy with what and how it's used. It won't be to enable an artist to pursue their passion, it'll be just enough to keep you quiet and docile, no more.