Yeah.... i'm pretty sure they are canceling these Monday shows because nobody is going to them. Also taking stars off the shows to have the wild card rules is only going to make less people buy tickets for those Monday house shows.
Exactly. People aren't going to house shows when all the top stars aren't going to be there like usual because of the wild card rule. Want to see Kofi at a house show? Not gonna happen. Reigns? Not gonna happen. The New Day? Nah, they'll probably be on Raw supporting Kofi. They've had to refund a lot of house show tickets because of this which is costing them money.
The way they're going they might as well scrap the brand split, since they can't even stick to their own rules on it. Ideally you'd want them to scrap this shit idea of a wild card and actually build up some wrestlers to get people watching, but that's clearly asking for way too much.

WWE have just pulled another House Show from their list of events, making it one of quite a few now. The funny part is the reason though. It's because it would be going up against Raw (all of the house shows have been Smackdown ones) and their options were have a weak house show because of the Wild Card rule (which is a joke in itself since they can't even stick to the 3 people rule - there were 5 Smackdown wrestlers on Raw this week alone), or they make Raw weaker by having them on the house show. Or they just cancel the house show like they have done.
This is the 5th time in 6 or 7 weeks that they have cancelled a House Show for this reason.