I don't think they care about ROI for real. If they cared none of that would've happened because that's just not how a real businesses are operating. You can burn the investments into R&D to an extent but if the product's money flow doesn't show a positive dynamics long enough - you get ready for some soul searching shit. My guess is that a lot of things contributing to AI bubble have something to do with money laundering.

These valuations cannot be tied to ROI, even using Olympic level mental gymnastics. The market would collapse in a millisecond. They are tied to a fictional dimension 78 years in the future where everyone decided to work overtime without collapsing and being four times as focused while the planet magically starts healing itself and no major disaster happens and all wars escalated without destroying any infrastructure or upsetting any populations and the authoritarian revenge hypercapitalist disasterpiece currently boiling over in the global standard host country suddenly is unanimously accepted as a new way of life without a single adverse reactions or any systematic issues and a spontaneous miraculous salvation from the diseases and famine it has maliciously developed due to the Christian god both existing and subscribing to the polar opposite moral and ethical alignment that the elite privileged promille has hallucinated to fit a reality that also somehow pivoted from a complete mass psychosis into firm truth by way of some unforseen quirk in the laws of physics that every great mind and scientists missed that magically flip childish commercial folly into concrete reality without requiring effort and being the first consciousless entity to achieve autonomy and an ability to replicate exponentially without consuming resources and a renneissance of unity appears around a unilateral decision to kill brown skinned people that agree to live and reproduce in the most efficient manner for the single purpose of feeding that slaughtering machine and producing goods and resources for the machine and for the now sanctioned debauchery that the new religion has prescribed all of our species to perform

Which as you might imagine is more than a little stretch