There seems to be quite a bit of speculation and opinion in this thread. One of my pet peaves about the chameleon community is that people often state things as fact or imply things are a certain way. There are no experts in the chameleon community when it come to understanding what chameleons need or how their husbandry should be. We have so much to learn and I feel like we are just at the beginning. When people do actual research some of these things will become clearer.
Considering how few captive breedings that have resulted in actual babies in the US and other places in the world and how little information has been shared about what has been successful and more importantly what hasn't been successful, I don't think we are at a point where we can make definitive statements about Parsonii health or reproduction.
Can female Parson's lay infertile clutches? I'm pretty sure they can and in fact I believe I've heard this happening but from what I've seen it's no where near what we see with veiled chameleons or do I think we can manipulate female Parson's the same way to keep them from laying infertile clutches.
We have to remember the prior to the ban being lifted there were probably only 20 or so Parson's in the US, now there are probably hundreds so we will be learning many new things about them as people experiment with different techniques in housing, feeding, breeding and egg hatching.
I've been keeping Parson's for a mere 6 1/2 years and I feel like I'm still a newbie. There is much more here to understand and learn than what meets the eye. IMO.