Of course I understand that money is only part of what we get out of work, and that we all choose our jobs for our own preferred balance of what this job gives us compared to other jobs we could do or else not working at all. Eg salary, other perks (eg festival organisers seeing the bands), job satisfaction, type of work (eg outdoors/people-focused), working conditions, number of hours, flexibility, ease, convenience, location, commute, personal ambition, development opportunities etc.
And obviously people will accept less of one benefit (eg salary) for more of another (eg job satisfaction).
That's not exactly rocket science or hard to understand.
Oh, and it's not better or morally superior to choose job satisfaction over salary:it's just personal preference. Many people would hate my job, but there's no job I would prefer - otherwise I'd switch. But relaxing with my family in the garden for the same salary would be preferable.
But you said
In reality many people’s motivation to work is not that they’re better off than they would be on benefits
It's a delusion to imagine that a significant number of people would choose to work instead of take benefits if that left them no better off.
For most people, their motivation to work is exactly to be better off than they would be on benefits
Otherwise they would take the benefits and volunteer for 40 hours a week in a role which gave them even more satisfaction (a job which didn't need to pay a salary could be tweaked to their preferences and made even better than one which was constrained by having to justify the cost of the salary).
Which for most part, benefit claimants don't.