There is a big difference between water pressure - which could damage the plumbing,
and water flow - which is how well your shower works.
Yes, folks can use brute force and force water with high pressure, or they can find out what restricts their flow, and fix the problem for good.
How many and what type water filters do your have? Some can restrict the flow significantly.
How old are your water filters? If you have sediment filters, they are designed to clog up as they filter our particulate matter in the water. They have to be replaced regularly.
Is there a reducer washer in the base of your shower handle which cuts down on the flow of the water?
Have your checked for calcium or other deposits on your water hose ends, the pressure reducer? If you see them, then those hard water deposits are also building up on your faucets and other internal plumbing fixtures.
I would never run without a pressure regulator, no more than 1 year old, between the 'city' water supply and my rig. It was 44 PSI when you checked, but it might be 100 PSI in the middle of the night, and 30 PSI at 7 am as everyone is getting ready for the day.
You also likely have a very good solution to the lack of flow problem built into your rig - a fresh water tank and a pump. At samboree's the water pressure is usually inconsistent - so I fill the fresh water tank and use the pump so I have consistent, steady pressure and flow.