If EVERY pilot participated in the "walk out", there is no way they could fire everyone. If they fired everyone, the skies would be quiet for 2 months. Reagan fired the controllers because they had a "no-strike" clause in their contract. They quickly replaced them with military controllers. It would take weeks alone for the airlines to do TSA required background checks on new-hires.
It is fun to think about, but we as pilots could never pull it off. What we could do, is write up airplanes at the most inconvenient outstation. Could you imagine if we did our job "by the book". Delay the flight to write up a reading light for seat 24C. After landing at "BFE" airport, write up the nose wheel has excessive vibration. Again, if EVERYONE would have at least 1 write up for every flight, we could create havoc. But it would only work if all pilots from all airlines would participate, this will never happen.