HotJava, IIRC, was more focused on Swing apps. Swing just wasn't the right thing for users; the HTML DOM turns out to be more comfortable. Even though it means sometimes failing out to the Canvas, which gives you nothing.
NB: I was very distantly part of the Swing team. I did early reviews of its design documents.
Considering we have full replacement frameworks like React, Flutter, etc built as DOM replacements, I would say Swing was definitely the right thing for users. Probably could have offered an "easy markup enhancement" library for plain documents, but anything extensively dynamic should be written with a proper UI framework.
It's a hard sell for the majority of users and the mainstream market at the time. Flash apps had cute, lazy loaded, ~lightweight, animated mini apps. Anything java at the time was heavy, enterprisey, requiring more setup to get blocky GUIs that didn't do much.
NB: I was very distantly part of the Swing team. I did early reviews of its design documents.