Bro part 1 of Naruto had over 150 filler epsiodes and part 2 had over 300.
and it turns out there is 3 parts a time skip and a 5th ninja war.
The difference here is that the anime always had chapters to adapt,the amount varied and so filler arcs would pop up between cannon seaons and yes some cannon seasons included filler to varying degrees sometimes to the point that it verged on majority filler and that is not even including episodes that basically amount to recaps through the use of flashbacks BUT, Boruto has only 15 chapters to go off of and all these chapters take place after the current period the show is focusing on.This means the filler will significantly outweigh cannon material by a considerable margin(Especially since the manga only proudes one chapter a month).So two hundred episodes of filler may be inaccurate but does not seem far from the truth.
I honestly do not expect much from this series and will probably watch an abridged version of the show once a good amount of cannon material is out.