This data center build frenzy reminds me the commercial centers build frenzy of 30 years ago. They were built with the expectancy to get an anchor and all the small shops filled, and people getting there to buy groceries and other stuff. At the beginning it worked, but after some time they got to saturation, because in these mall you found the same shops, and you clearly can't eat at two McDonalds or KFC at the same time and people started to go to the nearest mall, maybe the one that was at walking distance.
Normally the mall that are still thriving are the one near residential areas, but there are some commercial centers that had some parts that were built but never opened.
Then of course e-commerce happened and some types shops, like appliance and electronics, become empty, or basically a pick and pay for orders made online. Anchors resumed to make smaller supermarket for basically groceries near residential areas.
At some poiny some city councils stopped to give permits to build malls and there were a lot of protests. On the other hand there are more and more dead malls or dying malls, and the same could happen with data centers: because now they look profitable and everyone want to build one, but what will happen tomorrow, and the demand for service is finite and will split.