I am 35 and I am at the frontline for 12 years (therefore an infant for some here). Fortunately, I managed to keep up successfully with every *new thing* that has happened during this time. And many things have happened... I started with web development then I additionally did some mobile development, while participating in data mining projects on the side. I skipped IoT emergence and earned a master degree. I shifted to scientific programming while wearing my hats of the past whenever it was necessary. I am currently struggling to complete my PhD and I work as a research engineer in the industry.
Actively following the progress is very demanding but fulfilling. I guess that you are such a type of coder too. Maybe you are a window to my future. Each of us, a piece of our time.
I will share with you what I could/might try to do if I reach 50-60+ years. First of all, I believe a lot in the advancements of machine learning and quantum computing. It will be a time that my hands-on skills won't be on demand if I stop following the progress so aggressively. We will also interact differently with our tools and systems. However, I believe that my experience would allow me easily to delve into the current state of technologies if I wished to do something more practical at the time. It would take me a short period to become up-to-date and I would use whatever latest tools and resources are available to get up to speed. Like in the old days. Maybe, I would also try to assemble a team of younger people and work on something that bridges my expertise with the current demands. Another possibility is to get into educating newer minds, sharing my accumulated of experience of decades. Some experienced people take things for granted and believe that the younger ones already understand some concepts automagically. I do not make this mistake.
You could try using the emerging AI tools and checking the vast online resources to get a glimpse of a newer programming language, then try to build a process on moving legacy systems to modern codebases. Then implement/refine it with a team. Assistive technologies do not scare me (I work on these). I see a big chance for older folks in tools like ChatGPT and Github Co Pilot. Just don't be prejudiced (please).
P.S. I hope I did not offend anyone with my opinions or suggestions. It was not in my intention.
One is open source and the other is enough closed. However,I think approaching both platforms is the way to go.The more platforms you support
"What man has done, man can aspire to do." -- Jerry Pournelle, about space flight