You have the freedom to withdraw or deposit large sums of cash money, it's at the complete discretion if the banks will allow you to do so in lump sums or not.
As for the idea that the banks are trying to lock down your money so you can't access it? It's not stopping you withdraw your pay/pension each week. It's stopping large lump sums being shifted around, which would hamper illegal activity.
I would not sell a car/bathroom etc and accept $10k in cash, for the exact reasons I outlined. The effort you'd go'd have been through to buy something in cash would make me question why you were trying to deal in cash.
Even look at it from the security side of things, I've met with essentially a stranger to buy my car for $10-20k. He has brought cash, I have not been able to verify his identity, and now he knows I have $20k in cash that I'm carrying around until I can get to the bank. Seems like an easy target.
Or, is this money even legitimate? How can I tell if it is counterfeit?
You have the freedom to buy almost anything with cash, but I also have the freedom to say I don't want to accept your cash payment and I will only accept bank transfers.
Cash might be king, but the time of physical cash is behind us.
