Ya know, that’s the problem with the English language – a single word carries multiple meanings, the context determining the meaning meant. Take things out of context, and now you can impose whatever context your mind wants to. So…
Dictionary.com lists 13 meanings under “Professional”. Two of these talk about earning money; two also talk about being “expert” or “knowledgeable (consultant/trainer)”. So, one can be a “professional” in the sense of earning money, but not necessarily being good at it. AND, one can be a “Profession” in the sense of being very good at something but not necessarily earning money at it. However, ideally a “professional” should be good at it as well as earning money.
When it comes to earning money, there are various levels as well: “beer money”, “supplemental income”, “primary income” and “profitable enterprise”. The level of money-making depends on marketing, selling (the art of making a ridiculous price appear reasonable), cost-control, execution, and post-sale support. These are the realm of the business-person, and unfortunately often the technical skill set of the practitioner (photographer, plumber, personal trainer, financial advisor, etc.) is overshadowed by other attributes. Therefore, calling someone a “professional photographer” tells me nothing other than they made some money at it.
Given that the market for any service is usually woefully ignorant about the service, the standards, and what is involved, (if you doubt this, think about the “dreamy” photographs that some wedding party is gushing over, some expensive but cheaply-built home that the buyers think will appreciate 100% per year, some “investments” that appear almost too good to be true, and TV-order knives that will stay sharp after sawing through industrial I-beams…

. So just because someone sold something to someone else… doesn’t mean it’s good, or worth it.
So much for being good just because you got someone to pay for it.
Moving right along to the other meaning, where someone is a “professional” because of their knowledge, ability and results, doesn’t mean that they need to be making money at that activity to be called “professional”.
In the ideal world both meanings would reside in the same person. In the real world, maybe yes, and maybe no. Caveat emptor.