Yes, it would indeed be magnificent if we wouldn't even think of sinning,
and would always do the right thing ... but that depends on what you mean
by "the right thing".
For what the early philosophers considered to be bad, "the sort of acts
that would make the person who'd never want to commit them (indeed)
loftier than someone who does want to, but who subdues his yetzer harah so
as not to" as Rambam puts is, are things that everyone considers bad.
Like "murder, theft, robbery, fraud, harming an innocent person ... and
the like". Every decent, civilized, reasonable person would agree that
those are inherently wrongful acts, and that good people wouldn't do such
things or have much trouble avoiding them.
But the sorts of bad acts that one would have to struggle to not commit,
and which he'd be admired for not committing, are the kinds that aren't at
all inherently, manifestly wrong. They're what Rambam terms “authority-
based” prohibitions, or things we only know to be wrong because the Torah
prohibits them. Who, for example, would imagine it wrong to eat meat and
milk together, if left to his own devices? What's wrong with wearing wool
and linen together (known as "shaatnez")? Who would ever have thought that
it's wrong to cook on Shabbat?
In other words, if knowing that it's forbidden, I'm tempted to eat
unkosher food, I struggle with that urge and finally determine to not eat
it, I'm to be commended for my strength of character and will have managed
to prove myself better than my instincts. If I'd only not murdered
somebody or robbed him because I'd come to realize right then and there
that would be wrong, then I'd only have revealed my baseness.
What's Rambam's point, though, in bringing this all up in this work?
Granted it's an interesting question and a clever resolution to the
dilemma, but it seems tangential and irrelevant to Rambam's overarching
intention to have us better ourselves. But what he's doing is underscoring
the fact that we only attain *Jewish* spiritual excellence when we adhere
to common ethical guidelines and Torah-based ones also. For one could not
be righteous in the true sense of the term as a Jew and not be sensitive
to Jewish values.
Rambam ends this chapter here, but there's another matter to touch upon
that he spells out elsewhere which we'll come to: how we're to repent if
we don't succeed in our ethical struggles.