Lyft and Uber drivers can run 24/7 - there is no designated open or close time. I've gotten ubers at 2,3,4 in the morning in plenty of cities. It all depends on if any drivers happen to be awake and available.
You'll be fine well into the night in that area on a Saturday, especially. It will be crawling with drivers.
There are typically 4,000+ at a GOO Show and about 250 stay for the post show tour. Plus the fact that the GOO House sits adjacent to a mall with a movie theater and a large entertainment venue in Dave & Busters and near many hotels. Being a Saturday night, there will be plenty of drivers in the area to be able to accept your request.
Sincere THANKS to everyone for all the POSITIVE answers...I feel very comfortable now...!!