Bleach has always been like that. It used to be so active in here at the beginning of this arc, and yet, here we are. I guess the slow pace rate that this manga was going made it loose it's "popularity" ...
Hence the overall lack of activity. This activity you speak of at the beginning of this arc is relative and that probably had to do with the fact that it was a new arc.
Frankly it already lost most of its popularity during the Fullbringer arc. It merely increased a bit with the prospect of a new arc, especially when you consider it was announced it would be the final one, but Kubo wasn't able to maintain the excitement.
When a new arc starts, you immediately have discussions about your expectations of that arc, but if the arc doesn't provide anything substantial regularly for new discussions, you simply run out of things to say.