Uber and Tesla are valued at 150B and 500B respectively, I'd say in terms of an ROI on deploying large amounts of capital these are both huge success stories.
No investment in an emerging market is a sure thing, it's an educated guess. You have to take a lot of swings to occasionally hit a homerun, and investing in AI seems like the most plausible swing to make at this time.
I didn't claim there's no positive ROI. I only noted that the breathlessly promised "trillion+ dollar self-driving market" failed to materialize.
I suspect the AI market will have a similar trajectory in the next decade: no actual AGI - maybe one company still plugging away at it, a couple of very successful companies whose core competencies don't include AI, but with billions in market cap, and a lot of failed startups littering the way there.
No investment in an emerging market is a sure thing, it's an educated guess. You have to take a lot of swings to occasionally hit a homerun, and investing in AI seems like the most plausible swing to make at this time.