a. Running your own toilet cleaning business.
or
b. Retirement.
Golden handcuffs are not going to create fulfilled employees. Just look around HN, golden handcuffs create runway and a strong motivation to use it.
Not that compensating employees well is a bad idea - particularly on a production line good wages create stability. The difficulty is that a production line has less outlet for creativity because the schedule is tight and creative time means shutting down the line. Once a company adopts the factory model, their options are limited and regardless of intentions, everyone cannot become a manager - only one or two will.
Not to go against the immediate interests of my fellow workers, but how often have we seen advice to people to build up a fund so they can afford to go off and do what they really want - 6 months in the bank (or whatever) to let them really test a theory and start on their dream project? The better you pay those staff, the quicker they can build up that fund and leave you.
Which isn't to say staff should be underpaid and glad of it! but that salary is only part of what keeps someone working where they are. Pay people fairly for the value they add to your business but treat them well and value their skills and intelligence and they won't need to move on to try out their dream because you'll be providing them a platform where they can test it and you can reap the profits.
Perhaps give your employees stock or the responsibility of making decisions in their specialty areas. Or, give them something like 20% time where they can be creative. Perhaps they'll create some beautiful, original woodwork that gets you press on your blog. Or, perhaps, it just enriches their lives and keeps them happy.
Rather than throw money at a problem why not find ways to increase overall satisfaction? If money is a component of that, then great, but it doesn't motivate everyone. Often times people are looking for a better quality of life outside of the workplace: things like more time off to spend with their families mean a lot to some people and, if executed properly, don't hurt your bottom line either.
As for more responsibility, just give people more say in how the company is run. If your employers are better at something than you ever see yourself being, they probably have insights that you would never have. Ask them. Implement their ideas.
I don't think people really want to feel overpaid or overextended any more than they want to feel underpaid or underutilized. If employees are asking for more money or more responsibility, it's probably because they feel underpaid or underutilized, not because they want excess.