I would change it from `can` to `almost forced to`. Since I am seeing nuclearisation live, here are a few observations.
Industrialisation is an inherently compounding event. Thus, it gets concentrated geographically. So you get "hubs" like a tech hub, a manufacturing hub, a finance hub, etc,. So if you study CS, you cannot just take a tech job in a finance city or an export city. You got to move to a tech hub.
So unless your entire family is in roughly the same line of work, it is very difficult to keep a joint family. In fact, contrary to the "more money less kids" hypothesis, the traditional "family business" families that continue to do what their ancestors did, tend to have more kids and live in joint family homes.
Even if a set of parents happened to have 2.1 kids on average, the chance that in the next generation, the two siblings end up consistently living close by each other is very small. So it really only takes 30 years for TFR to fall off a cliff.
