Load growth for the last 15 years has been very small but load growth going forward is expected to rise due to electrification of all things to decarbonize the economy. This means home heating, electrical cars, heavy industries, obviously data centers and the list goes on. So even if we have more grid capacity than demand (this seems unlikely), it will be used before too long.
Will just make capacity available for electrification of other infrastructure like heat pumps, electric cars, and so on. Lots of other folks would happily buy that power. The whole AI bubble is just driving up electricity pricing for everyone else at the moment.