When things are well made, and well thought out, they will sell. My point was that props aren't any easier of a sell then charactets or clothing in poserdom. Medium quality props won't sell better or bring you more money then medium quality charactets or medium quality clothing.

Sure, there are other 3d markets, but MistyLara has asked about Poser related content. Different 3d markets have different dynamics. That falls under researching your target market.

Some of the prop makers you listed here, I talk to on regular basis, and a few othes, not listed here, and I've done props myself and have first hand sales numbers too. Lot of content makers talk to each other, hang out, or on occasion collaborate. By all means, I would encourage that you verify the veracity of what I'm saying. This is not about who is right on the forums, I'm just offering some of what I leraned over the years of being a content maker. If you don't want the knowledge, or prefer to make your own mistakes, go for it. It only makes it easier for me (and other vendors) to stay competetive.

I have serious reservations about armchair quarterbacking someone's interest in making a living out of this, because there is a significant amount of misconceptions in forums, and I hate seeing people learning the hard way, and suffering losses.

I don't think anyone is disagreeing with what you've said here.  Most everyone that has commented has offered some solid advice. Misty didn't specify exactly what she meant by exclusive, and Poser isn't the only market available for content artists. If someone is interested in building a business as a content provider, then it's advisable they consider all their options. Limiting themselves just to Poser and D|S is ignoring a large chunk of potential profit in other similar markets, which often tend to command much higher prices per item - especially considering the process of making content for Poser requires relatively the same skill sets, so why wouldn't someone branch out and take advantage of that? Learning Unity or Unreal, or many of the other free and low-cost game engines out there is no more difficult than learning Poser. But I don't advise trying to jump into all of it at once. If you're most familiar with Poser, or DS, then that is what you should focus on to start and decide if it's really something you can see yourself doing full time. It's not exactly the easiest work and often requires long hours just to reach a satisfactory level of quality. But with time and practice things become easier and faster to complete.  

Notice also, Renderosity now offers extended licenses for their content artists as options - so that the content can be used in games - meaning that content needs to be designed to work efficiently in those engines with little to no additional effort on the end user's part. These additional licensing options, combined with Poser's Game Dev upgrade, should be seen as a sort of merging of two ends of the spectrum that have traditionally remained separate until recently. 

As for armchair quarterbacking, I suspect you mean speculation without experience, none of which is true from what I've said at least. I make my living as a content artist. I'd be making a lot more if I was more dedicated, which I intend to be. It's my new year's resolution, lol.