Once your basic needs are met, the equation becomes: Salary = Expenses + Savings. So, the questions becomes, how much savings makes you happy?
If you are happy to work in your job until "retirement age", a small savings rate will do, in theory; that is if the salary is adjusted for cost-of-living and tax.
Are you happy working this job for the rest of your life? Full time (whatever that means in your work culture)?
Yes, I'm lucky enough to have a good salary, but I can tell people there is no top limit. Once you have your needs met then you're exactly right, it's about retirement planning and savings, and there could always be more. The fact is that the only true money amount that will make someone happy is the amount that allows them not to work anymore