The longest government shutdown prior was 18 days, or one pay check delayed. If it drags on for much longer and several paychecks are delayed then you can't blame them for not being prepared for something that has never happened before. Eventually they will quit and do something else to feed their families.
Back in 2013, many of us of who were retirement-eligible found out that you can’t retire or quit during a shut down because the HR, OPM and other support staff are also furloughed.
I doubt anyone keeps theae kinds of records, but it would be very interesting to find out if there is a massive wave of retirements and resignations in the first few weeks after the government reopens. I won’t get into OMNI-land, but I will just post the speculation here.
I’m not sure we will see a mass exodus from the TSA because, as incredible as it sounds, they have been around long enough now that many of them are too close to federal retirement to simply quit and throw it all away. I will further speculate that those not showing up are the younger and less-tenured employees who don’t have much to lose.