There are $1.5k pro products and there are $5k pro products. In almost any industry there are entry level pro products and top of the line pro products. If we take pro as in used by professionals, because not all people have the same requirements.
So, the marketing of this product as being targeted for pros is vague at best. Because like you said, what kind of pro is it designed to? I just can't see it.
- Pro gamers will be better served by AMD processor + 3D card.
- Pro image editors might be served by it, but... most video-intensive applications are accelerated by the 3D card, and if you're willing to pay for it, the PC world has computers with better GPU acceleration options.
- Pro sound editors will definitely be better served by a Windows machine, which is faster and has better compatibility with most sound equipment.
That's very different with Apple mobile devices. Notice how they have much better selling propositions? No one can quite match the iPhone's video quality, stabilization and edition, and nothing beats the iPad in performance. But with Apple desktops? I just don't see a good selling point at this time.
If Apple had not dumped eGPU support, those entry-level machines could perhaps be considered a more serious choice. But I think they killed it because, for them, it blurs the line between higher and lower-spec machines. Why bother buying a computer with a more advanced GPU when you could get a Mac Mini, upgrade it, and get more bang for your buck?
Also, guys, I don't hate Apple. Quite the opposite. And it's because I like them that I'm criticizing them. When you only give people praise, they can't learn from their mistakes. Apple not learning from their mistakes here could eventually be very bad for them.