If you look at Rooster Teeth RWBY and several of the sessions of Red vs. Blue Poser is used a lot. The first two sessions of RWBY were made with Poser. As far as the Content issue there are a lot of factors in the problem. Poser 5 introduced the hair room and dynamic cloth. At the time it took a lot of computer power to run those features. Also at that time DAZ had their program and it had none of those features. SO content was made to the lowest common feature set. Over the years Poser has tried to introduce better ways of doing things only to be shot down because it requires people to learn new ways of doing things. And as we all know change is bad. So we stick to using a bug from around Poser 3/4 times to make clothing follow the main figure. It is to the point that if you were to make a Pencil Skirt that in real life would restrict the wearer to be able to move their legs maybe 12", in Poser the figure has to be able to the splits without the skirt tearing or showing signs of distortion.
The under supported figures were made by Poser/Smith Micro to show off the newest features of the program when it came out. The problem is that unlike the real world where you can go into a store and buy a pair of jeans in your size and they fit fairly well. In Poser each garment has to be tailor made to a specific figure or it would work correctly. Since V4 was out for about 10 years as the only doll that worked in both programs that is the default figure things are made to work with. Poser allows you via the Fitting room to take content from one figure to another with some work. Problem is that is work and people don' want to be bothered.

99% of the vendors are self employed and don't have a written work flow that they follow each time. One vendor I have almost all the Poser content for makes scenes and each of them is complete in and of it's self. The problem is the textures are almost always the same images, however they are located in separate folders labeled for each block. Probably has to due to store requirements that all the elements are labeled in a manner so you can track down the parts of kit. However it does lead to having 20 versions of the same brick pattern.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13