Why would you have that far of history on your resume? I only have 11 years worth of experience on my current resume and my year of graduating isn’t on there either. No one cares about my C programming experience on mainframes in the mid 90s nor my C++/MFC/COM programming up until 2008.
How easy would it be to get another job? That’s kind of the point. I found one or two C/MFC jobs back then but dozens of C# and Java jobs that I wasn’t qualified for.
If I need a job now, I want to be able to call my list of recruiters and within the next week have dozens to choose from and 3 or 4 offers which has been easy to do between 2008-2016. When I was looking in 2017, there were more companies looking for Node and full stack developers paying what I was looking for than C#. I happened to find a job that needed my combination of C# and architectural experience, but the pickings were getting slimmer.
So now, as much as I hate it, I’m going down the full stack JavaScript road because that’s where the opportunities are, and filling in a few gaps that will let me be an overpriced “digital transformation consultant”/“cloud consultant”, etc. (Yes I die a little every time I say those words).
One skillset is about getting a job fast if needed the other is by getting one that pays more. It’s about optionality.
When you are still trying to be a software developer in your 40s you can't afford to not keep up. Companies are far more willing to let younger people learn on the job than older, presumably better paid old developers. They already stereotype us as not being up to date, no need to reinforce it.