I can't think anyone has check-in closure times which are deliberately onerous as a revenue-generating measure from people who then miss flights as a result. Airline check-in times tend to be a function of wanting customers at the gate by at least STD-20 to commence boarding for doors closed at -5 and an on-time push. It also takes time for bags to be security screened, reconciled and loaded and then to get the loadsheet, weight & balance and consequent aircraft performance wrapped up before push. Check-in closures have everything to do with OTP and very little to do with revenue.