Things change. Sometimes you are in control of the change and sometimes you are not. In my opinion, working at the same place for 20 years is way too long..makes your skills stagnant and less competitive. Everyone should be proactively managing their career for when these things happen. I would imagine it would be hard starting over after that long of time...every 6 months one should be analyzing their career and seeing what new skills they have picked up that can transfer to different industries etc.
This is a nice piece of advice given by @VOLtWoJ-3gqi . Think that we all need to be aware of the constant threat of losing our job, even if we are long-time workers, and that we need to be ready when it happens.