It is more a case of investment money seeking a growing sector in a sea of shrinking sectors. Demand for AI may dry up in the medium term but investors are looking at the short term for now.
As the article says some tech firms are cash rich with a falling USD. If the dollar keeps heading down they're basically losing money so investing in AI data centers at least shows some growth currently.
A possible fall in AI demand is down the road. They have to either keep kicking the can or give up and move to NZ bunkers.