Adult Swim being the only major non-indie brand to really jump on the whole Steamboat Willie thing is funny because, looking at what enters the PD in the next 2 decades, Warner Bros. easily has the most to quote-unquote "lose" of the big 5, by quite a margin too. The Hobbit, Superman, Batman, Tom & Jerry, and the Chuck Jones/Tex Avery Looney Tunes are all big money-makers for WB and will be PD by the end of the 2030s, as will their specific takes on the Oz imagery. The other 4's tried-and-tested IP pool - including Disney - leans significantly more recent.