Okay I'm answering this off the seat of my pants because I don't have the time to do research, but here's my explanation:
Warp factors have consistently gone through a re-proportioning process throughout the Star Trek universe. In the original series, there were ships known to travel at warp 10 or even faster. In the episode with the Nomad probe, it improved the efficiency of the engines so that the Enterprise could travel at warp 11. And there were a few other instances of high warp factors.
Then in Star Trek TNG and beyond, it's mentioned as a plot point several times that warp 10 is the absolute "speed limit" of the universe, like the speed of light is to us now. If warp 10 were ever reached, funky things would happen. I remember reading a TNG book about <PERSON>'s sister who had a relationship with <PERSON> and hated the <PERSON> because of what they did to her species, and to get to them faster she propelled this ship up to warp 10 and then disappeared from our universe, because at warp 10 you exist simultaneously, everywhere. 126
(supposedly)
So what happened is a reproportioning of warp factors so that the ultimate speed is now designated as warp 10. That means in the original series, all their 10+ warp speed figures would now be revised to warp factors somewhere under 10.
The 24th century warp factor scale with warp 10 being equal to "infinite speed" and ultimately unachievable pretty much held steady throughout TNG, DS9 and Voyager. Of course there were all sorts of other technologies, like transwarp and slipstream and whatnot, but for regular warp factors, the barrier of warp 10 remained. (and if people tried to break it, well you saw what happened to <PERSON>).
Now for All Good Things being inconsistent, for an out-of-universe explanation, I think the writers wanted to give a "futuristic" sense and try to show that technology progressed in the intervening years. For an in-universe explanation, we can say that Starfleet for some reason once more re-scaled the warp factor measurements so that warp 10 was no longer the infinite speed.
Here, I pulled this quote from Memory Alpha, which confirms this:
In the October 1995 issue of OMNI, science advisor <PERSON> stated the idea of warp factors beyond 10 in the alternative future was in a recalibration of the warp scale, as ships had gotten faster. Maybe warp 15 was set to be the transwarp threshold instead, according to <PERSON>, and warp 13 in that scale would have been the equivalent of warp 9.95 of the previous scale. 126