CPU improvements are only part of the story in making that happen but the are certainly far ahead of where things were in the not so distant past.
You're desperately moving the goal post to ridiculous places. It's like claiming that walking on the moon is supposed to be considered normal just because the technology has been ready for a long time.
That claim is irrelevant, isn't it? I mean, what good does a "technically it's possible" claim do if a) no, it's clearly not possible outside exceptionally rare circumstances b) the average consumer device is way behind any of those outlandish claims.
The fact alone that you're talking about using/adding a nonstandard and exceptional battery is more than enough to throw out that claim.