A trimming of exclusives is a reasonable choice, if they release them at the current rate the supply will be just choking. It is already choking. I predict they will also slow down a little and release them ~every 2 months. We don't need this many at once. An average LEGO collector just can't keep up.
Regarding the end of modulars I believe that is unlikely. Why? Because there exist more marginal exclusives that don't sell as well, I don't know if you noticed but PR was a top seller the whole year. The line has a steady customer base. Less risk for LEGO than the Mixer, Maersk stuff, Sydney Opera etc. If I was LEGO and had to keep only one line, it would be the modulars, second would be SW UCS. Companies like predictability. They don't kill their steadily selling products, rather they trim the more risky ones. Modulars also don't require any license.