I'm honestly not sure what to make of that given that you downplayed the issue to sound like nothing and also implied NV cards have the same problem.
AMD has been catching a lot of flack for the issue in recent years since they never offered a proper solution to fix it. nVidia jumped on it much sooner. A few years ago, they released a software-based approach as well, and then followed it up with a hardware solution. I don't know the full details of what that means, but I'd be willing to bet it's about 50% effective and 50% marketing. Whatever it is, it works, but it's not perfect.
Of course, you can't eliminate it completely*, but hardware solutions do go a long way. Does NV even have frame pacing in their drivers? I'm not aware of it if they do (I can't say I've particularly looked very hard though). I think the difference in architecture alleviates the issue much on its own.
* That is a little too strong. Some clever hardware engineers may make the issue a thing of the past at some point. You never know. Operate on the same clock tick somehow?
Again, they have bragged about some kind of hardware solution, but I don't know the details. I'm sure there's a software fix in their drivers somewhere as well. Even today, nVidia cards do suffer from microstuttering issues as well. It just doesn't get much attention because AMD/ATi has overshadowed them there. It's an inherent problem with any multi-GPU setup, regardless of which vendor is chosen. As you said, maybe there will be one day in the future when it's not an issue anymore, but I don't see that day on any calendar for the next few years.