I think what's more important then canon is something like an analog of continuity from calculus. A function can be continuous everywhere, which is analogous to having perfect adherence to a canon. It can also have major discontinuities (like 1/x at x=0), which I think of as like a reboot. There are even single-point "removable" discontinuities (like x²/x at x=0), which can be fixed by adding a single point to a function, are more analogous a tiny detail being wrong that doesn't affect anything else and can probably be fixed with a simple retcon if anyone even cares.

You can do all kinds of calculations that depend on continuity of a function as long as they're restricted to parts of the function with only removable discontinuities. Similarly, you can tell perfectly good stories in a broken canon as long as the story doesn't focus on things in the canon that are broken. Each individual story needs to maintain its own continuity (or else we say it has plot holes), but discontinuities between stories don't matter as long as stories feel like Star Trek to the audience.

Of course, feeling like Star Trek is very subjective, and feeling like a bunch of connected stories share the same continuity can be very satisfying, but overall, I agree with Nimoy that fans should just relax and not let discontinuities ruin their enjoyment of a good story.