Star Wars technologically plateaued ages ago

And yet, they don't have computer-aimed turrets. They still rely on people getting into turrets and aiming at their targets using some kind of low-fi 1970s era CRT to assist them. They may have plateaued ages ago, but it seems like their plateau was pretty low. They never developed transporters, they never developed replicators, AFAIK they don't have cloaking devices. They have robots, but the robots seem pretty primitive in a number of ways -- certainly they don't have any robots that are advanced enough to be mistaken for humans / humanoids.

It's also hard to estimate the power of "laser" cannons based on what you see on screen.

On one hand, a specialty space station was created that was powerful enough to blow up an entire planet in the matter of seconds. Even if the weapons they use for ship-to-ship fire are 1000x less powerful, 1/1000th of the power needed to destroy a planet is absurdly huge. Maybe the weapons are incredibly powerful, but we don't know because the shields are also incredibly powerful.

Meanwhile, the Star Trek world only got warp drive recently, so recently that the individual who created it is still in living memory. But, just because it's recent doesn't mean they're not even more technologically advanced. Everything we see in Star Trek suggests that they blew past the plateau that Star Wars hit, and kept going. Transporter beams, replicators, holodecks, limited time travel, androids with positronic brains that can pass for humans, artificial intelligence both at an individual scale (robots and sentient robotic aliens) but also at larger scales, like the ship's computers.

Maybe in Star Wars world, there are no really advanced aliens, so all the alien races got brought into the same empire. Since there's no outside influence creating pressure to come up with new technologies, there's technological stagnation. In Star Trek's universe, they keep finding new aliens, many of whom are so advanced they're godlike. That has to keep inspiring inventors. In addition, instead of one giant empire, there are multiple empires, many of whom are hostile to one-another. One thing that tends to result in technological development is arms races against aggressive neighbors.

I tend to ignore what they say at places like stardestroyer.net because the more you look into these Sci Fi universes (and probably the George Lucasverse more than most) the more contradictions and paradoxes you see. I find I can enjoy them more if I just let my imagination fill in the details, based on what I see on-screen.