How is React better for large-scale apps exactly? Are you referring to some ecosystem parts?
Good question.
To be honest, I think it's a matter of opinion. I think most developers would be fine to use VueJS for a large scale app these days. I'll give you the reason why I think React > Vue for large scale apps.
Size of Community: If you're building large apps, you're going to need lots of developers. These developers are going to run into bugs and problems and with a larger development community, you're more likely going to find a solution for these problems. Also the large developer community means you have a larger talent pool to draw from. (On the flip side, Vue is easier to learn than react, so ramp up time for new hires would be smaller with Vue).
Breadth of 3rd Party Packages: Depending on what your app is, you're going to not want to write everything yourself. One of the great things about react is, generally speaking, anything you want to build, is already out there in some way shape or form. VueJS is definitely on its way for this, there are some really amazing design libs for Vue. ( Vuetify, VueSax ).
Structure of Application: I personally like Reacts schema of organizing components over VueJS schema. So I am biased there. However, if I were to offer an unbiased opinion, a good JavaScript developer should have no problem working with either framework to build and organize a killer large-scale app.
Hope this helps. I appreciate the criticism and prompting me to explain my point of view ;)
Paweł Świątkowski