Exactly. These guys have their 6 figure incomes, pensions, healthcare and set for life. There is no personal gain in adding few more desks in the office. It is a real reach to say the added value is the ego of towering over a few more subordinates.
Not a very likely theory in my opinion.
Now, saying repubs will cut the head off the snake so keep us out of prison if you want to keep that cushy 6 figures/pension is very likely motivator.
YMMV
Power over a bigger bureaucracy.
Also, a bigger government to weaponize.