How to resolve a conflict when both sides are right

Do you need some framework for this? How about a competent manager instead?

I've seen this pattern a few times now: someone encounters NVC - claims that his interpersonal skills have massively increased - starts trying to recruit others into it - others don't follow because he's mostly talking in canned robotic phrases - when others point it out to him, he uses NVC tools to ignore/deflect - all efforts to reach him fail. In contrast, I've never seen anyone who could be described as an NVC success story.

It helped us a lot by putting in a simple low bar for professional communication and conflict resolution, and as a training mechanism. Startups get wild in unpredictable diff ways, so need to have something.

In practice, older team members did not need it as much to begin with, so they quickly got it. Mid/younger benifited more -- less experience in channeling passion and handling problems?

Main issue IME can function as a smothering mechanism that lets things fester. Even if a discussion remains cordial and makes progress, that does not mean the conflict gets resolved. Ex: folks can just stop talking. So useful but incomplete, and the article title overclaims.

IMHO this stage of NVC lasts about 6 months, and it is rarely "doing NVC" - ie; if you get really angry/scared/etc you prob haven't built up the muscle memory yet to even reach for those canned phrases (probably applies more in more intimate relationships than the workplace - partner(s), parents, kids, etc) but maybe you do, and surprisingly even a clumsy canned phrase about your own feelings or needs rather than jumping to an accusation of the other person can still help ratchet down the tension.

After practicing NVC a fair amount (it is a /practice/, not a tool), you can literally start feeling your brain re-wire in a good way. You stop feeling so much responsible for other people's emotions, even if they are about something you did or needing to put your needs in contrast to someone elses, you start automatically being able to empathize with someone's feelings, even when they might scare you, and perhaps most importantly your own self-talk and the way you relate to parts of yourself that "you" are in conflict with starts to change.

At this point, there is much less robotic phrases. In fact, watching someone who has many years of experience rewiring their own defenses through NVC practice responding to difficult situations seems near-magical because there are so many less ego defenses to get stuck on someone elses ego defenses so really difficult and hard things can be cut through like better and both people can feel heard and understoor.

Based on the title alone I would say "find the most important aspect of each side's view and come up with a compromise that satisfies both parties"

I've done this several times now and it hasn't failed me yet. The hard part is discovering "the most important aspect of each side's view" because sometimes they themselves don't know it without some probing.