That being said, there is something compelling about an older engineer who constantly re-invents himself with the latest technology.
That's the point I'm trying not to make. Are you building a startup that's effectively a CRUD app? If so, sure, that's pretty much all you need and is why coder schools have become so prevalent - they get you to a practicing point that covers the bases of most small websites and very, very basic startups.
Age and experience brings with it something vital: the ability to build long term pattern recognition of technology business cycles, the "all is old is new again", the ways that novel technologies may fall like their predecessors. This is not something you learn in a CS program or even a few years out of college. It's something you only learn by playing with tens of languages and mastering six or seven over decades, by constantly learning, by being part of those business cycles. This skillset is often discredited and is enormously valuable, but I believe it requires a tireless passion for novelty and modern technique to become a multiplier on skill.
No. After four years you know just about enough to inflict a really nasty case of the second-system effect on some unsuspecting customer.
My biggest to date (but not the only one): having received complaints, I figured in 2 days that the culprit is the change in the manufacturing-workweek-number of the DDR ICs. It took them several months onsite with people travelling from abroad and with expensive equipment to find the real root cause, and guess what they have found?
And I am not even a hardware engineer. How did I do that? Intuition. You need lots of time to develop intuition, much more than 4 years, and once you got it, it saves lots of time and money.
I have also seen other experienced engineers do this sort of tricks, and I pity the workplaces where people aren't familiar with this.