Yes, printed boarding passes are still available should you prefer to not utilize a mobile boarding pass. You can print your boarding pass online, at the airport using a self-service kiosk, or from the ticket counter on the day of departure, prior to your flight's scheduled departure time.
Should I print my boarding pass at home or at the airport?
There have been multiple cases where mobile scanners go down, cell reception doesn't work, or you just have technical phone difficulties at TSA or the boarding gate (the two times when you have to flash your boarding pass). Smart travelers print their boarding pass at the airport.
Is a screenshot of a boarding pass sufficient?
Yes, you can use screenshot of your boarding pass. All airlines offer the option of a mobile boarding pass as an alternative to printing yours or picking up a paper copy at the airport. In case you lost you phone or paper boarding pass it always works in that time.