My recent experience on the forum on Bob Cozzi’s RPGIV website underlined the fact that I am not in contention for the title of “World’s Best RPG Programmer”. I posed a question that involved the use of APIs and prototypes, and I submitted my sample code. I got my question answered, but not before it was made very clear to me that my abilities as to APIs and prototyping were considerably below cutting edge.
How do you get to be a good programmer? You have to be intelligent, which can mean you have to know when to be as stupid as the computer. You have to be intolerant of errors. And you have to be willing to learn from your mistakes, as you will make thousands of them.
But beyond these basic qualities and attitudes, other circumstances may determine how deeply you will get into the more arcane aspects of your chosen programming language that will allow you to be among the “best”.
For one thing, your circumstances have to be such that you are exposed to advanced programming techniques. This will likely also be a function of your intellectual curiosity. But perhaps just as importantly, your circumstances have to be such that you will actually have a need for these techniques. You may never be in a position where you will need to access user spaces. While you may see some benefit to variable length fields, you may not see any burning need to start using them. And while much of the benefit of ILE is built around things like APIs and prototypes, it may well occur that your site simply does not need a wholesale conversion of code to make use of called procedures.
As it happened, my experience above came as a result of a need for them. Two-digit years are still used on my system. In calculating the maturity date of a 30-year loan written in 2010, I bumped up against the ILE default for two-digit date fields (1940 to 2039) and got an “invalid date” error when I attempted to generate 3/15/40 to represent 2040. To get around this, I decide to use an API I was aware of, CEESCEN, which allows you to float the 100 year range you want to use for the 100-year period in question. This is used in association with APIs CEEDAYS and CEEDATE to allow you to format dates in numerous different formats. (Google the API names for details.)
However, I was not familiar with how to set up the prototypes needed, and as a result I made some stupid mistakes that leaped out at the knowledgeable participants in the forum, especially Bob. But anyway, with some help, I got the prototypes and program calls to work.
But my learning things like these are in response to a specific need. I don’t have a burning need to learn all or even a substantial portion of the APIs available. I simply don’t need them. The fact is that I am getting paid to write production code, not specifically to “learn new things” . And the fact is also that I am not in a position where I can spend a lot of time outside the workplace learning new stuff, since family and other personal needs and circumstances have first claim on my time.
Other people, by reason of education, career choices, and the employers they happened to have, may have had open to them early in their careers opportunities to work on truly advanced concepts that I never was exposed to and likely never will be. Of course, their being smarter than me, not to mention better educated early on, would also make this more likely 
My task being to maintain and upgrade code that was from the 1980’s and 1990’s in style, if not always in vintage, I will likely be kept busy doing that for the balance of my career. I like to think I’m good, but I’ll never be the best.