That leads to the judicial branch actually making the law and not having a consistent set of rules depending on who the judge is.
Do you want to build a business based on the whims of a judge when you thought that you were following the law?
Also see: https://www.bloomberg.com/opinion/articles/2019-03-07/the-fe...
...in which Matt Levine juxtaposes the concepts of going by rules versus what he calls "legal realism".
The problem is then nobody actually knows what the law is until after the judge decides it, at which point they're essentially creating new rules ex post facto and applying them to past conduct. It's manifestly unreasonable to apply a rule that wasn't known until five minutes ago to actions that took place last year.
> Trying to enumerate every legal interpretation and eventuality based on today's conditions and technology results in a law that won't be meaningful 5 years from now.
Which means you may have to pass a new law in five years -- that's not a bug. For that matter, if you expect things to change significantly then you may want to make the current rules expire in five years automatically, or hold off legislating anything at all until you see how things shake out on their own.
No, precedent is foundational to common law, not western law as a whole. There are two main forms of western law.