It's because there's all sorts of bonus tax implications to getting property improvements activated as quickly as possible before tax law phaseouts begin in 2023.
I'm not a tax lawyer, so I can't talk specifically about Comcast, but basically the expensing depreciation bonuses will begin to phase out after 2023. So if Universal wants to take advantage of those, they need as much built as possible by December 31, 2023. They'll still get bonuses in 2024-2027 for improvements, but each year they lose an additional 20% of the bonus I think.