Yet they’ve never needed to commission power plants to dedicate power to these facilities.

Never?

huh? every data center i've been to has hundreds of megawatts of stand-by power generation which is regularly used to take up slack, because data center loads are peaky as hell. when facebook was building their first european datacenter in 2012 they were heavily criticised for their planned local power infrastructure, which was and still is diesel generators. the one being built in my area, which is a colo, has planned for over 700MW of local generation despite being built next to multiple hydro dams.