A good PCP is great as a gatekeeper.
I don’t have many medical issues so seeing my PCP is mostly a yearly thing. Go over my blood work and determine what I need. I now take medication for my higher blood pressure. My PCP is new and this year I think I will forgo the GYN and have her do what is now a 5 year routine Pap smear. She makes sure all those routine tests are done and all those vaccines are up to date. So I schedule those colonoscopies and mammograms. I see a dermatologist because of past skin cancer and I’m in that queue so no need to follow up with that. But a PCP serves a purpose and that purpose is for continuity.
My husband has more complex medical issues and his PCP serves a different function. He sees specialists for the stuff that is wrong. But the PCP has all the information in one place and can address any problems that will occasionally pop up. He was in the hospital recently and had a weird issue come up that he went to the PCP for. It was addressed but the doctor noticed that husband had some genetic screening done. PCP noticed that some additional screening should be done and made the necessary referral.
This is getting long 
. But if you never see a PCP, then I wonder how easy it is to keep up with those tests that are infrequent but necessary. I’d hate to find out later that I’ve missed something routine. Such as a colonoscopy or high blood pressure or high cholesterol. I also know that specialists can be myopic and address what they are experts at and not looking at the whole picture.
This is how medicine works in theory, doesn’t always work in reality. I think my husband and I are lucky to have found good PCPs