The undeniable fact is that there will be a case for any scenario, and that fact is the essential driver for code inflation. You can't shed the code since that code is there for a potential case; and you can't help adding code as you keep discovering/imagining new cases.
This is where a bit wisdom differentiates people. There is no winning trying to match exponential generality with our finite ability. So wise people seek essence and accept the reality that there will always be cases that are uncovered and the important thing is not to lose the essence -- bury the essence amid mountain of glut is not much different from losing the essence, therefore, it is often more plausible for the minimal approach than the bloat. The essence covers 80% of the time and the rest 20% of the time we cope with it.
In the case that you might not be using a shell and when you need the true/false such as with parallel or find? Why not write your true/false program then? In fact, I write my own parallel script every single time when I really need parallel. It is not hard. Takes about the same time for me to go through the man page.
Like, say you have a program that uses a user-specified program + arguments, like parallel or find -- but for evaluating a boolean condition.
true/false would help.