In humans there's a psychological phenomenon called "crowding out", essentially it's hard for our brains to attach multiple, powerful incentives to one activity. Generally the "lesser" ones get crowded out by the more important one.

I'm still young (26), and still feel the same way about programming, I deeply enjoy it. However, I know programmers who were passionate like me when they were younger, and that passion has been slowly drained as they continue to code professionally, and I've seen it come back when they move into non-programming roles (be it industry change or moving to management).

Generally you won't find yourself wanting to program 40 hours a week, 48-50 weeks a year, for 50 years without a substantial break, and yet that's what capitalism expects of workers. Yet you'll continue to work because there's a more important incentive than passion, money.

You need money to survive (food, shelter, etc.) and your brain understands those are more important than fulfilling a passion, that's why you'll go to work even if you're drained mentally. You'll continue to do that forever so long as you don't have the financial freedom to do otherwise (which is the goal of capitalists, this is why we have COL-based incomes, so as not to overpay people who live in cheaper areas as it'd allow them the freedom to leave).