Even the DoE posts top 500 results when they commission a supercomputer.
Comparing their crazy expensive custom built HPC to massive arrays of customer grade hardware doesn't bring them additional funds, nor help them more PR wise than being the owner of the fastest individual clusters.
Being at the top of some heap is visibly one of their goal:
High precision HPC exists in the private cloud, but you only hear "we don't want to embarrass others" excuses because otherwise you would be able to calculate the cost.
On prem HPC is still very, very much cheaper than hiring out.