Disney+ also has a bundle offer for Hulu, and ESPN+ as a trio. Disney just recently reassured shareholders that Hulu was their focus for all of Disney's less "family friendly/family focused" content (Miramax, much of the Fox catalogs), including that the FX/FXX content programming team is moving into building Hulu Originals in addition to cable content. Disney seems keen on differentiating Hulu enough from Disney+ that they may not cannibalize the Hulu audience that much. (Probably the thing for Hulu to worry about much more than Disney+ is the expiration of their deal for Comcast/NBC Universal content in 2025, and the ghostly specter of whatever weird plans Comcast has for "Peacock".)

From people that work at Hulu, the current strategy is for Hulu to remain the live-streaming/online DVR option for broadcast shows, and to be the sreaming platform for experimental and adultish fare like Always Sunny, with Disney+ remaining the family-friendly/mainstream/prestige streaming platform in the Disney suite.

Here's a source on the FX team working on more Hulu Originals:

https://variety.com/2019/biz/news/fx-hulu-disney-mrs-america...

It also mentions that Disney has asked Fox Searchlight to consider more of its project slate for Hulu Original instead of theaters, which aligns with how much Netflix and Amazon have been investing in independent films for (nearly) straight to streaming distribution.