Quite the opposite, which is my
point. The Species 8472 beat the Borg hands down without
using their so-powerful-that-adaptation-becomes-meaningless supergun....
They didn't need superguns. Turns out there Unusually Large guns were more than sufficient. When you've got a weapon that can slag a Borg cube with two hits or less, adaptation is irrelevant.
And this is less exciting than "shoot at them until their ability to regenerate gets overwhelmed", how?
For the same reason "Aliens" was more exciting than "First Contact."
Because you can't really fight
something that slowly and invincibly ambles down a hallway like a mechanized zombie. At a certain point you're reduced to screaming at them while slowly backpedaling and looking really tense, but that isn't a fight
as much as it is an obvious waste of time.
Picture the "Last Stand" scene from Aliens, only gump some Borg Drones in place of the aliens and add a scene of a couple of those drones -- having already been shot to pieces -- scooping up their entrails and literally pulling themselves back together until a fully-functional condition. Ultimately it has the same dynamics -- your security team winds up being chased down a hallway by invincible drones -- but the difference is that 1) it actually makes sense to shoot them now because your shots have SOME effect and 2) mechanical zomies getting shot to pieces is a lot more fun to watch than mechanical zombies with CGI forcefields on their chests.
An adversary that simply takes more shots to kill than yer average Klingon sounds just about as boring as adversaries can get...
Except they don't die, they just get back up and keep coming, again and again and again, pretty much forever. Which means you're up against an enemy that can't be killed, not because it's indestructible, but because destroying it won't actually kill it. It's a bit like the Flood from Halo 2 and especially 3. In addition to the fact that you get to watch some of your own Marines transformed into mutant killing machines right in front of you, sometimes you gun down those killing machines only to watch them reanimate themselves, get back up and start attacking you again; you have to kill that same mutated marine three or four times, and by the time you've done this your shields are down and you're almost out of ammo.
Anyone can blow up a ship, but Borg ships just slither back together and come at you again. You can only blow it up so many times before your phasers burn out and your torpedo bays run out of ammo, and then they've got you.
And this is not adapting for what reason?
In the same sense that Worf wasn't "adapting" when he dialed his phaser up to a higher setting. They didn't analyze his weapon and come up with a countermeasure, they just sent a tougher drone.