There are many ways to "feel useful" that don't require the exchanges of power and time required by employment. There are -used to be- many channels of social contact available, beyond employment.
We're building a society where "holding a job" becomes the only avenue of social interaction and fulfillment. The problem is that "holding a job" is a lousy way of social interaction and fulfillment - work can become an tension filled environment where friendships are hard to form ; fulfillment is not so easy to come by when doing someone else's bidding.
And our capitalist societies aren't shaped to provide "good jobs for everybody" ; the producticity requirement in much of private employment, the fact employers want full time employees, and that our automatising societies don't require as much human labour as it used to, converge towards more and more unemployment.
We can decide to force our societies into the full employment paradigm of the twentieth century, or try to change them towards a different paradigm - did you see Martin's diary about Basic Income ?
The rentier of the 19th century didn't seem so depressed about not being productive... Un roi sans divertissement est un homme plein de misères
I agree that there are other ways of being engaged and useful but the challenge is changing societies where it is a badge of honour to appear on daytime tv shows like Jeremy Kyle - think Jerry Springer...
It's a problem that is so deeply ingrained in the UK that I can't work out where it begins or ends or where it isn't. It ties in with everything, the education system, the principles of 'welfare', inequalities, employment...
The scenario you wish to present - how do you shift the paradigm to begin to move towards that? Ad astra per aspera