They had a really good core in my opinion. The overall performance and especially the prototype preview was really nice. Every change was instant and not even heavy animations were a problem. Much nicer than the Sketch slideshow style prototypes and Figma prototypes that load very slow, not to mention the bugginess.

Judging by the 20bil price they wanted to pay, I guess they know what kind of investment would be needed to compete now.

XD never took off. If Adobe wants to get into the UI market they would need to go back to the drawing board and start from scratch. If you're starting with a failed product you're most likely going to fail again.