That's about average at a busy time, which is increasingly common. (On a good day, arrival doesn't take even that if off quickly.) That is, arrival is usually -- actually almost always -- faster than departure, given the times of day we are talking about here for both.

It used to be a lot quicker both ways a couple of years ago, but now the hordes have made it what it is.

Given my status with the airline (i.e., frequent flyer status or biz/first ticket) and familiarity with the process, I usually show up 80-90 minutes before departure. It used to be I'd show up 65-75 minutes before flight departure, but now the extra 15-25 minutes are needed.