This will probably be a very unpopular opinion but I definitely feel that men innately need this struggle.
Improving the chances for success for your offspring is an innate desire, removing the ability will affect people's motivation to contribute beyond a certain point. A tax on inheritances will allow you to improve your children's life while removing the wealth if a family chooses not to work for a few generations, thus motivating contribution beyond "I exist and I inherited money".
Either way though, it might impact motivation negatively.
Your opinion cant be removed, everything in life can be reduced down to biology if you accept to lose out on certain axioms.
But I rather like your "need for burden" theory as well.
Having a job where you get up, go out, do something useful, and interact with others is good for the soul. Sitting at home by yourself watching TV is a recipe for decline and death.