No doubt that the Web has shuffled the cards on the table, redefining (and sometimes making undefined) boundaries between “pro” and amateurs, a theme which I have already addressed previously, in a different light.
My opinion, in general, is that the “litmus test” come when you decide to print.
A print of adequate size hanging on a wall, or a photo book, represent a satisfaction and a commitment immensely more than a few “likes” on social networks, comfortable refuge for “poser” photographers.

Even an amateur can try to create a book, I think it could be an incredible stimulus to improve technically, to develop a well-defined creative and think of their work in conceptually articulated terms .
In short, a real project.
So why not try?
With a service like Blurb can do without a publisher, printing a lot (you can also limit the “edition” copy-once) and, if used “pre-cooked” templates, you will not have worry to typeset.
For a keen amateur photographer might be a good idea to target for some months its activities to a specific project, perhaps with the aim of printing a few copies of a subject that could become an original gift for friends.
Blurb offe, then, the ability to market their books also.

But that’s another part of the dream