That's why I offer a retainer package. Get paid for just being available when needed and work a non-conflicting contract elsewhere.
No, I learned how to manage my work load (potential and actual) from clients for my physical/mental health.
The motivation is what determines the actions.
I know a guy who founded a software company and started contracting work overseas. He became too confident and over-committed to clients without managing expectations. For a couple of months he looked terrible. Thankfully, he found an escape path and closed the company. He's now employed full time in a dev role.
This path isn't for everyone.
"Hey I'm already up to speed on this so if you want to pick it up again quickly ...." proposal probabbly would seem like a good idea to the company for a while at least.