The idea is to drive out older, less-pliant potential employees, in favor of newer ones, who can be molded into a shape the corporation prefers.
Have you ever seen a couple that has gotten married later in life? Many times, it may be a second (or more) time for one or both of them.
They need to make massive compromises. Both have gotten used to supporting themselves, and keeping their own counsel. They generally both have a lot of property, maybe grown kids, careers, etc. Usually, they don't actually need each other, for more than emotional support. They each do fine, on their own. It's a relationship of equals.
It can be a challenge to make it work, but when it does, it's amazing. I have known many couples like that.
I understand why corporations don't want to put effort into working with older folks, but it can be well worth it.
So many times, when I see these awful, Jurassic-scale disasters, made by companies that are staffed exclusively by younger folks, I say to myself "That was a really great idea, but they completely pooched the release. Why didn't anybody raise any red flags?"
The answer is generally, that no one on staff had enough experience to understand the ramifications of many decisions, and often, they were afraid to countermand ideas put forth by their superiors.
Couple that with 20-something CEOs, who are often fearfully insecure, and you have a recipe for disaster.
Like I said, not to invalidate anything, these experiences are so common amongst the whole pool that it has to be weighed accordingly.
(Not everything people say online is true.)
It wouldnt take me 700 hours to get familiar with all the abstract problems and concepts I’ll encounter, but it would take me a very long time to, and longer to synthesize solutions that are above average, and regurgitating that on the spot for an interview in a quicker time than other candidates.