No. The last major term extension was a perfect storm of Germany, Disney, and everyone else in the industry bullying around the EU and US to go life+70. Mickey Mouse was also arguably one of Disney's flagship works back then. This was also in a world where copyright was a boring part of the law nobody cared about except the people who benefited from it's imposition.
This isn't really the case anymore:
- Copyright law was already harmonized up. There are very few countries that regularly grant longer terms: Mexico, Columbia, Jamaica, St. Vincent and the Grenadines, Samoa, and Equatorial Guinea. None of those countries are international dealmakers and I do not see the US or EU raising terms to match them.
- Disney's flagship properties aren't Disney works anymore. They're the Star Wars and Marvel universes. Those have greater cultural cachet, remaining copyright terms to match, and Disney owns them lock, stock, and barrel. Snow White isn't even their own work; it's a German folk tale that the Brothers' Grimm made a children's version[0] of, a century prior to Disney's animated adaptation. The characters and story are already public domain, Disney only owns an animated adaptation of it.
- In the sense that Disney might not fully control the Marvel Cinematic Universe, they stand to benefit by weakening copyright (so they can stop having to share Spider-Man with SONY), not extending it.
- There's less appetite among other creators for longer terms. The big hot-button issue with authors is the market power of large platforms; the sort of thing that can't be fixed by just lengthening terms out more. Furthermore, the Sonny Bono act was pushed through with a promise that the extra licensing money publishers got would result in more artists getting more money; this has not happened and I don't think they'll get fooled again.
- Stop SOPA/PIPA happened. Furthermore, thanks to a combination of YouTubers having terrible copyright discipline and actual scammers using DMCA 512 as an extortion mechanism; there's far more public awareness of the downsides of having strongly-enforced copyright laws.
[0] Ironically, the Grimm versions of these fairy tales are perceived as more "hardcore" and "uncensored", mostly because Disney softened them down more.