I think there are a lot of poor and somewhat fair photographers out there working as "professional photographers" because they have a website and price list. The number of skilled, experienced and talented photographers out there is a much smaller percentage. Notice I didn't include the word professional the second time. IMHO, the word professional only indicates the fact that the photographer charges for their services and hopefully can pull off the job to the clients' satisfaction. The word professional in no way vouches for the quality of the work. Today's great (or not so great) professional is merely yesterday's up and coming amateur. Everyone has to start somewhere.
It's all about the individual. For example, there are many "photo moms" out there that are "professionals" because they do photography as a part time side business and it helps pay for their gear. This is how a lot of professionals start out. It's only after a lot of time and work has been performed that the photographer gets better in all aspects, be it working with subjects, scheduling, billing, delivery of images, whatever. Like anything else, the more you do it, the better you get. And you only improve at what you do. If one never ventures outside their comfort zone, they don't grow much, they just improve in that niche they are in.
Like most things, you get what you pay for and mediocre photographers won't get away with charging what highly respected and reputable photographers with a following can charge. (For good reason.) It's up to the buyer to be diligent and look at the past work and references of any provider of services. I look at the wedding pictures we have from our wedding in '95 and I'm blown away. And of course they shot with film then. Mostly medium format. At this point in my photography experience and with the great gear I currently own, I think I *might* be able to duplicate maybe half the shots if I was really lucky.
There is no replacing skill, talent and experience but it can be earned and the photographer doesn't have to be paid to earn/learn it. So with that said, IMO the only thing that matters is the work. Some non-pros will easily shoot circles around some pros and vice versa. And I think Wedding Photography is perhaps the hardest and most demanding photography out there. It's essentially journalistic photography in all the hardest situations but with a demand of top studio level excellence and quality. My hat is off to all good and great wedding photographers. All others have my sympathy.