I think that it’s because now we’re starting to get judges who have an actual understanding of the internet and its issues. In the past, lawyers for copyright holders could make up whatever theories of it they wanted and frame things in whatever way benefits them the most; that’s no longer the case - these judges (including the original trial judge, the appeals judges, and the Canadian Supreme Court, who handed down the original decision at stake here) plainly understand in at least a basic way how the internet is used, what an IP address is, and the complexities of assigning responsibility related to one.
Whereas ten or twenty years ago you would have had judges who mostly depended on the plaintiff’s lawyers for their understanding and who would therefore basically give them anything they asked for.