False. You can be motivated by things and then change your mind if the circumstances change. If they passed a law that said anything in excess of what I made now would be taxed at 100%, I would not have any interest in going above and beyond for a raise or promotion. I would not go back to school to get a graduate degree. I would just do my job satisfactorily.
Again, I don't claim to know what they would do. But I can speculate just like you can. There currently is no law that puts people in this position. You are basing what you think they would do off of what they do now. When you take choices away from people, you are bound to get push back. Do you honestly think that the majority of wealthy people would be happy with this law if it were to be enacted?
When you tax someone 100% of all money over a certain amount, it is punishment. It's punishing the inheritors because their family made too much money. Who cares if the kids earned it or not? I don't. If the family created some new engine or invented the transistor, why would it be a bad thing for them to pass all of that money on to their children and grandchildren?