These are all talking about max capacity too.

The 172 is more likely to be full and the pilot has a good chance of being part of the group instead of just a pilot.

The 787 is likely to be at least 90% full and the crew are a much smaller proportion of the load.

If there are just two people missing from max capacity on the Learjet then that’s making things even more inefficient than the others. And it’s very likely that they will be at least that much under capacity.