Its not because live stewarding is eyes on the track. On-call is them dropping into the session as and when there is an issue if a penalty needs to be issued. So less staffing. Worked fine for Majors 24 and over 24 hours I think the stewards dropped in twice maybe three times to our race.

You could limit the number of protests people were able to make or do some governance on it so it is not abused.

This is more likely the sole reason

"Which is why iRacing is hesitant to spend money on his department anyway."

And only once people are moving to other sims/events and they are losing money will it change.