You have a desire to be able to write scripts, but you're afraid by the time you learn those skills will be obsolete.
Some words of wisdom, success is where opportunity meets preparedness. If you're not prepared, you can't take advantage of the opportunity (scripting on the game) and it'll just pass you by.
Pause. Relative to your specific situation... If you learn how to script, there is 'longevity' in the programming you will have learned. That knowledgebase is applicable outside of just Runescape scripts. There is value in that.
On the other hand, you can prepare all you want, but if the opportunity doesn't present itself then you should still be glad that you put in the effort. That within itself is an accomplishment. It will count for something. Which circles back to what I mentioned earlier in there being extrinsic value, there may be a different opportunity laying ahead that you don't know is coming. And when it enters your scope, you will be prepared.
∞∞∞∞∞