I think utility is surely a significant factor in motivating humans to learn some topics. If you're retired, you're unlikely to take much interest in mastering

I think utility is surely a significant factor in motivating humans to learn some topics. If you're retired, you're unlikely to take much interest in mastering Jira or getting CPA certification or a six sigma belt — skills you'll never use. Likewise, if future prospects for using a skill seem more limited with age, you're very likely to be less inclined to pursue means to such ends. Or perhaps mice just relish sugar water less as their taste buds fade with age.