There are some prolonged effects, this is why it works as a treatment for things like depression. But those effects are not dramatic. It takes many sessions of r TMS to engage in any kind of substantial brain modulation that lasts for more than an hour or less, and the case like something with Broca's area which is a very well entrenched functional area of the brain, if one was to perform for example a single prolonged rtms treatment session to reduce activity in that region, the effects would be at best extremely subtle. That would think most likely not really able to produce any significant deficit. Because the effect of a session of rTMS and modulating the brain more long term is fairly minimal

As in the video linked above, when you actually fire the rtms you cause some destruction or noise in the underlying cortex, which can be used as an experimental method to see how different parts of the brain are involved in different tasks. For example, I did some work during my PhD where we used our TMS to disrupt memory formation by interrupting activity in the prefrontal cortex. This is different than rTMS used as a treatment intervention, we call this the perturb and measure approach