The private engagement in Canada seals the entire narrative for me.
Meghan made it clear in her pre-Harry life that her ideal life path would be, and I forget the words or phrasing, essentially highlighting causes and serving as a sort of patron for highlighting issues close to her heart. The only problem is, there is absolutely no demand for that unless you are one of two things: fabulously wealthy, so you can donate to those causes on a big-impact level, or incredibly famous, so you can inspire enough other people to donate to make a difference.
So Meghan meets and falls in love with one of a handful of people in the world who can give her not one but both of the things she needs to fulfill her dream, but also puts in her a position where she can't really do it. She can't just highlight the causes close to heart and form connections how, when, and where she thinks she can make the most impact.
And the narrative here is that, through no forethought but through totally unforeseen and unexpected outside forces, here we are less than four years later and she is in the exact position she needed to be in to fulfill her lifelong dreams but without the restraints holding her back. In fact, less than a week after the announcement, she is out there doing what she always wanted to do (using her wealth and her position to privately influence causes) while her husband and his family deal with fallout a continent away.
This is why people predicted from the very beginning that the situation we are in would emerge. Meghan told us where she wanted to end up. It should be no surprise that she got there.