Most people don't have a water pressure problem. The main line almost always has more than enough pressure for your home. It has to, or the fire hydrants wouldn't work. And by law, the hydrants have to work. The main line also has more than enough capacity (usually, though the infrastructure can lag in quickly developing areas). Again, it has to or the hydrants wouldn't work. So, what happens in your home? Your pipes are undersized. And why are your pipes undersized? Because the plumbing contractor who installed the piping was a lazy, cheap yewt who didn't know what he was doing.

Most modern homes with their three bathrooms, dish washer, clothes washer, etc, should have at least a 1" line feeding the entire home. 1-1/4" would actually be preferable if you do the math and design it by code. Most builders are still only installing a 3/4" line. Why? Because it's cheap and it's what they've always done. That's simply not big enough. You can do whatever else you want in your house, but if you only have a 3/4" main line, you will always have the mislabeled water pressure issue. Only it's not a pressure issue, it's a flow issue caused by the fact that you can only flow so much water through a 3/4" line.