The OP has a funny conception of Mr. Ford's career, if he thinks TFA "revived" it. Looking at his filmography, one could argue he's never ceased to be an A-lister, and even if he did, the spell certainly didn't last all the way to 2015.
Ford's rock bottom was arguably between 2002 and 2008. After starring in the K-19 Widowmaker in 2002, he did only two movies between the years mentioned, Hollywood Homicide (2003) and Firewall (2006), both of which were considered not very good.
If there was a year that could be considered a "rise back to stardom" (if he ever lost it), it was 2008, when he starred in what was his last movie where he was the undisputed leading man, and also what's been his biggest BO hit to date in such a role (at least as far as the raw numbers are considered, since it's often been said we should look past those, with good reason). And the movie? Well, I think everyone who stumbles upon this thread should know what it is.
Since then, Ford has mostly starred in a continuous string of respectable movies, both critically and commercially (Morning Glory, Cowboys & Aliens, 42, The Age of Adaline), though maybe they weren't huge hits and one could say he's never got back to where he was in the 90s. His last top billing was Crossing Over in 2009, but that was an episodic movie, so we could say his final leading role - to date at least - is that little movie we don't talk about.
In fact, it's down right hilarious to say his career was "revived" by TFA, given the friggin' sample size following the piece, which to date consists of Blade Runner 2049. And even that piece, while a critical success, was a BO failure. (Incidentally, just like the original.) Not to mention despite using Ford's presence heavily in marketing, neither film itself was a vehicle built around him. Heh, following TFA, Ford's even done voice work, in LEGO Star Wars - The Force Awakens video game, and in the upcoming The Secret Life of Pets 2, and such work is not generally considered a sign that an actor's career is going uphill. Though this might be another piece of intellectual dishonesty, since the respectability of such work has improved, along with its production values.
While we can say that Mr. Ford's star did sink a bit coming into the new millennium, it never sunk to a level requiring a "revival". And the reason for the initial sinking is simple - he aged. And before somebody gets his knickers in a twist, let it be said that there's nothing dramatic about it. He simply hit the typical career bump various other A-listers have when they reach their mid-50s. That's when producers start looking for younger stars for their biggest blockbusters. Yet it doesn't make the previous top dogs Hollywood pariahs. They still keep receiving work, and it's good, respectable work - and sometimes they even get top billings - but the glory days are gone.