Oh sorry, you seem to have interpreted my reply as asking for a load of drivel based around your opinion of what or what isn't graphic design. I was more trying to work out why you care so much, you do what you do, thats great, why are you so fussed about what other people do?

For some reason web and mobile app designers started splitting this function apart

Well, it's pretty simple really - there a load of 'graphic designers' that decided to do digital, they don't do it very well. Digital specialists emerged, often called web designers. The web matured, and simply being a 'Web Designer' wasn't really an accurate reflection of what we do.

At some point in that timeline the notion of a UX designer appeared (previous similar roles to an Information Architect, for example).

Then people started splitting UX and Visual design into separate disciplines. Thats fine, it makes sense from a company resourcing perspective, it’s easy for hiring managers to get their heads around. The problem is that some of us are hybrids - we’re at home defining scenarios, personas, flows and wireframes as well as executing polished visuals. Some do a bit of research too, others maybe a bit of front end work.

Going into a company with that hybrid approach, into a world of ‘Visual’ and ‘UX’ designers doesn’t work. You often end up doing one or the other, and hybrid designers like to cover more areas to get a better understanding of what they’re designing and it’s scope, strategy, user goals and business goals. We needed a term for this role, so we could make sure we were talking to companies that worked in this way.

Increasingly, lots of App’s, be that native mobile or web, were defining themselves as digital products. Often, the companies who saw their output as ‘Products’ were the ones that adopted the modern approach that hybrid’s usually fell into best. It made sense to go ‘well we’re designing digital products, we’re product designers’.

It’s worth noting that at this point, the notion of digital specialists calling themselves Graphic Designers was long gone. Terms like Digital Designer, UI Designer and Visual Designer were by far more common for digital specialists to adopt. In the minds of lots of companies, they hire Graphic Designers to their communications department, while they hire UI/Visual/Digital Designers into their Product department.

It’s vital you understand that this isn’t some trend thats come about because designers thought it sounded ‘cool’. If that was the case we would have lots of designers calling themselves ‘Product Designers’ applying for roles with different titles. While that still happens (it takes a while for companies to catch up), it’s pretty compelling that some of the largest companies in the world have adopted the title of ‘Product Designer’ and actively hire for it. (Just take a look at any digital job board).

which tells me perhaps you really aren't graphic designers

Absolutely, I’m not a graphic designer. Thats the entire point. Not from the elitist ‘you’re not a real designer’ approach that you meant it, but from the ‘Yes, I have an entirely different skillset’ approach.

but you're still not product designers because you're not designing products, you're designing web and mobile apps.

If your career has been focused in Agency or Ad Land, I get that this can be a difficult concept, but todays Apps are products. They’re digital, but they’re still products. If, in 2016, you’re genuinely diminishing the sheer scale of thought and work that goes into the scoping, defining, designing, executing, testing, researching and iterating that goes into ‘designing’ a digital product down to ‘You just do apps and websites’, then, quite frankly, you don’t have the first clue about the job you seem so angry exists.