I switched jobs to software development at 30 to go from $34k to 45k (note that I made a bigger jump at 30 than in all of my twenties.
I'm in the process of switching to a job that pays $115k, two years later.
Do I wish I'd done this a decade ago? Certainly. But if you're sitting there thinking "my twenties are over, I'm done," think again and go learn something new.
This article is just fear mongering. If you belong to the group of people reading comments on HN, you are able to drop in and out of the work force as you wish and do whatever you want with your life. If you want to maximize income in your 20's and reap the rewards of early investment, fine. If you want to travel the world now and jump in the game later, that's also fine.
More seriously, I laugh when former colleagues think of me as successful. It's correct that I've launched a successful product, but money is so random that I rather consider myself as "having fun and learning to launch a product" than "being successful".
What are you doing in your new job, out of interest?