Programmers make up a tiny percentage of the target market.
Being able to get more cores and CPU power than a top of the line iMac for cheaper than the base iMac helps a lot in any motion work. Access to Nvidia GPUs and therefore GPU rendering engines completely changes your workflow for 3D and product design work. Products like Surface studio are way more valuable to illustrators than an overpriced Cintiq or a TouchBar.
Ten or so years ago you'd see plenty of Macs on the cutting edge of creative work, not the case now I mean heck they can't even consume VR content let alone create VR content.