So, OK, work in the "knowledge field." Fine! That's what I do now. But guess what. They don't want you. Apparently everyone over 40 is dumb. No more knowledge. I'm seeing it first hand. I know this has been a problem for a long time, but it is completely out of control in the tech world. Millennials are treated as gods. We are upending our entire office culture to bow down to their wisdom. And when layoffs come, well you know what happens.
Actually, I don't think it's as bad as it used to be. I had heard and seen some of the "if you're over 40 you're out" in the 90's and early 2000's in the Bay Area. However, it has lessened a great amount. I was actively courted by one of the supposed bastions of youthful engineers when I was over 40. They kept at it for 3 years before I finally went in for interviews. I was worried that I would be old but 2/3 of the people who interviewed me were older than I was. I spent the last 7 years of my career there and I worked with people in a wide range of ages, some even beyond the "normal" 65 retirement age.
Some of the change is due to the increase in demand for good engineers and the limited supply so I don't know if it will continue.
Edit: I was thinking about this a little more after I posted.
I think there is something that can
appear to be ageism but isn't. The front running tech companies like those mentioned in the article (Google, Apple, etc) need employees who can effectively use the latest and greatest technologies. Over time the window of the age of technologies used at a company moves forward. An engineer who is knowledgable in only the tech that was available when they came out of school 20 years ago would find that there are fewer and fewer jobs they can do until finally there are no jobs inside the company that they can do. It is often quicker than 20 years.
To stay in the front most companies it requires one to keep on a constant treadmill of learning new tech. Some of it good and worthwhile and some of it nothing more than the same stuff in a new packaging. But it doesn't matter, you still need to learn the new stuff all the time. For older engineers this can be difficult. They have other responsibilities outside of work (aging parents, children, etc.), they get tired of running the treadmill, etc. Some of the changes are as simple as learning a new tool, some learning a new programming language, but some are complete mental model shifts that take a big change in thought process. The later can be hard to do and some don't make the transition. I saw that happen early in my career to older engineers and object oriented programming.
I'm not sure that anybody who works outside that environment really has any idea of the amount of work needed to stay current.