#2 Too small a pay-per-view for a cash in
We've all heard various rumors about the attendance at WWE Stomping Grounds and the poor ticket sales too. But because none of them have come from verified sources, I won't lend any credence to their authenticity. At the same time, when there's smoke there's a fire, and there's a reason why WWE is allegedly having trouble selling tickets for WWE Stomping Grounds.
Let's have a look at the last three big shows that WWE put on, to give us an idea. WrestleMania is the ultimate fan experience and it sells out, year after year. Money in the Bank has actual stakes and two ladder matches whereas Super ShowDown happened in front of an audience that is starved for good quality WWE action.
Compared to these three pay-per-views, Stomping Grounds was a very, very small affair. Having Lesnar cash in here wouldn't have made sense.