the jaegers at the time were using decent weapons. thats why the kaiju attacks were becoming more frequent and more powerful. was no need to use the sword, when it was used at the end it was something they tried as kinda at the last resort. there could be a number of other explanations as to why they did not use the sword previously. maybe the sword was defective, maybe it was too resource intensive. maybe they didnt think it would be as effective as it was, etc.
Except, that's not it at all--if they were able to build a mathematical formula off of the increases of attacks, then it stands to reason there was no extraneous variable, like weapons, that was affecting it. It was merely an exponential progression until the time between attacks reached a horizon where two would occur at once. Also, no--it has nothing to do with the Kaiju "adapting". The plasma weaponry on Gypsy was considered an "old" weapon by the final fight, and the most evolved Kaiju got his shit blown out by it. The reality is, from everything we've seen, the Kaiju merely go through more iterations to make them better in general vs humans, much like the Jaeger's constantly got upgraded to make them better vs Kaiju. Just one is using biological, while the other is mechanical.
But the big thing is? YOU, shouldn't be filling in that blank, Chuk. 30 seconds of exposition could have answered that question (Which is why I said 10 minutes of criticism, followed by edits, would have fixed it). The
LACKof the answer IS the problem, understand? It's not that we can't "think" of one, I can pull 20 out of my ass right now if I wanted. It's the fact that the director or writer didn't think of one. Which just shows that the actual story, was subservient to whatever got the big robots back on the screen again. Which, consequently, made, me at least, care less about the fights--so when dumb things happened in the fight, it was just another eye roll.
The worst part of that mentality, that "the story doesn't matter", is what produced the bland, one dimensional characters we didn't care about. Fuck me, the only reason I even cared WHO died was because I was like "Oh man, Stringer Bell died!". Because the character he was playing in this was so boring, so cliche and so unispired that I couldn't care less about him.
Onlythe fact that I knew the actor from another show even gave me a reason to notice that he sacrificed himself, and that's only because I was sad he wasn't going to be in the sequel.
I'm fine with stupid "lapses" in the science or logic of stories. Every movie is filled with them. But you can ignore them in movies and stories where there are other hooks. In movies where it's JUST eye candy, they become a lot more glaring. That was Pacific Rims problem. That's why the audience latches on to the things like weapon use timing, and other small details--because the fight scenes were the ONLY thing on this movies' menu and so they were dissected to the point of tedium--the audience was like a bunch of starving people breaking apart the bones of this movie to suck out the marrow.