Sad to know that your skeleton is not selling well. I guess muscle textures/maps probably will not sell as well. I understand where you are at. Anyway, will be looking forwards to your Indricotherium (Paraceratheriun), hopefully in the near future.
There have been a few horse skeletons for example, the Sixus ravaged horse from his cirque macabre set a lifetime ago and at least two more from our Asian content creators whose name I am sorry I no longer recall. I picked up most of them. I think one of them also made a cat skeleton but not sure,couldn't afford it at the time. So this cat skeleton is cool but I can see not having broad appeal. It is pretty niche product in a community where softer less dark art is more common.
Sometimes a product like this beautiful skeleton could sell better if art of a theme or series. Like what Sixus did with his old Cirque Macabre where many items were created to sell separately to work alone or together u dear the macabre circus tent idea.
If I could model I would for instance, create, something like a big cat but not a recognizable species more like a fantasy war cat and offer morphs and textures and tac for it as well as add-on vehicles. The idea being if you show a variety of ways it can be used more diverse user base might see something they can use it for.
When I go to Renderosity for instance, sometimes the few sample product images used to market the product are not enough to give me a good taste of what the product really can be used for. It sometimes isn't until I look through the product gallery that I get a better idea seeing how it was used by others and it is usually those images that will sell it.
There are too many single use stand alone products out there as there have always been, that get released without further support or add-on expansion products that just die for lack of clarity or growth options and support really.
I think the cat skeleton could be one of those kind of products.....beautiful but when and how will I be able to use it?
Just a thought.........