20-Year Prospect
In case you haven't noticed, major motion pictures aren't exactly diminishing in popularity. Entertainment is still really big business, and most people who work on films should see better-than-average job growth over the coming decade. That includes sound editors—which, as a field, is expected to grow by a whopping eighteen percent by 2024 (source).
The reason for the extra growth is the explosion of mediums in which high-quality films and shows are presented. Thanks to video blogs, internet media channels, and the like, the opportunities to edit sound should grow quite a bit in the coming years. That's great news for you would-be sound editors.
It also means you need to keep up with the times. The internet is changing things—especially things having to do with entertainment—at a blazing fast rate. In twenty years, all the equipment and techniques sound editors use could be completely different—so keep up with advancements and keep your ear to the...headphones.