It does mean others could copy and distribute the work at their leisure. You can upload Steamboat Willie to YouTube, Wikipedia, or wherever now and there is not a thing* Disney can do to stop you.

The actors could have it in their contract that they get residuals for infinity years, but there’s not much of a reason for purchases to earn residuals from once the right of distribution becomes free to all.

*Not legally, at least, but YouTube is bad at checking legality of takedown requests