The old schism over Genesis... DS started as a possible replacement for Poser, but then ended up being the redheaded stepchild. Eventually, Daz saw Poser's overall market share eroding, and theirs along with it. However, being stuck with Poser's quirky archaic rigging system, there was little they could do. They'd already stretched it as far as they could with V4. Daz begged and pleaded with SM to implement weightmap rigging, SM just wasn't interested. So, Daz had to make a hard choice, stay the course with Poser and continue to sink or implement weightmap and other new tech to grow their own marketshare independent of Poser. From what I understand, they continued pleading with SM while developing Genesis, but they just wouldn't budge. Their eventual response was adding "capsule" rigging zones to their old system in Poser8, which neither they or anyone else really supported. Up to this point, the schism wasn't Daz's fault. It was entirely on SM and Poser.
I'm not sure what eventually got SM to change course, but they did eventually take weightmap seriously and opted to shoehorn their own implementation into the old Poser format. Around the same time, looking to appeal to markets beyond Poser, Daz had decided to move to an entirely new DSON file format. Not wanting to invest in two formats, SM stuck with their implementation. Trying to bridge the divide, Daz did attempt to bring the new Poser9 format into DS4.5 (implementing parts of it), but eventually gave up and stuck with their own formats as well. Instead, Daz (sort of) buried the hatch with SM and worked to make an importer for Poser. That was, and still is, hit and miss because there are some advanced features that Poser doesn't support and likely never will. Though DS can read most Poser9 version weightmaps, it doesn't understand other changes in the rigging format.
That's basically what we're stuck with now. There's always been a rift between DS and Poser on some features and implementations. However, SM and Daz don't collaborate at all on new features. The current bridge isn't going to span the rift as it continues to grow. If SM wasn't such a stubborn mule, things wouldn't have gotten this bad between them.