Nobody can code - forever - with what they learn once.
Code requirements change.
It's human made. We write it. We use it. We realize we can make it better. We do.
Younger people come along, see what we've done and think, "I can do it faster - I'll spend 2,000 hours focused purely on making this faster while I'm in University. The folks working the 9-6 don't have the extra time to improve the code.
As the young people improve the code and the tools and the coding eco-system - we all have to upgrade.
New chips are developer. More code.
New computers ( phones ) are developed with new screen sizes and new touch capabilities and lots and lots of code.
App opportunities - new code.
New compilers are required to run this code faster on the different hardware.
If you learn to code - you can just learn enough to do something you want to do. You can build your own 200wordsaday and decide on the scope and depth of how much technology you'll implement. You can even limit what you do.
On the one hand, you can definitely code.
The reason we're saying nobody can code -- is because it's a huge memory requirement to keep the fingerings for all the code 'instruments' in your head. Most of us rely on Google constantly to find help. In that sense, it's likely that people don't code widely and remember everything on their own.