You can only get grid connections if the grid thinks they can support your demand. That’s why grid connections take so long, they’re not just plugging in a massive cable, they’re reinforcing other parts of the grid to make sure your massive cable won’t cause a blackout if use all the power it can provide.

Building new power plants immediately isn’t really required to serve data centre, they’re huge amounts of spare capacity in most grids that only exists for extreme situations. The hard part is making sure any existing capacity can actually be delivered to the new data centre. New power plants will get built to rebuild spare capacity over time, or more likely, solar and wind will get built to reinforce that spare capacity over time.

Datacentres are useful grid loads because they all have backup power on site capable of powering the entire site as an island. Which means grid operators can ask them to disconnect quickly if they need to extra power for short periods of time to handle power spikes, or local grid faults. So it’s possible to connect quite a lot of extra data centre type load before generation capacity becomes a serious issue.

> Which means grid operators can ask them to disconnect quickly

Really, now? Yeah, they can ask, but do data center operators just go "oh grid needs our power! Let's switch to backup!"

That seems unlikely. Why would a data center (or any large consumer of electrical power) be forced into a backup/contingency plan, when no crisis exists at all? Other than drilling/practice runs, I cannot see them readily agreeing to this. Is it actually a routine occurrence?