So a couple of comments there.
That first one is really basically irrelevant to any practical wind turbine design. Sure, it's great as a basic science demo for learning, but if you want to talk about maximizing efficiency and output, you really have to start with a design using lifting blades rather than cups (since you sacrifice so much with the cups that it's basically never worth it except at very small scale if you just want a simple design).
As for that second video, I'm amused by the claim that palm springs is the wind turbine capital of the US. In reality, northwest Texas and Iowa are the leaders in US wind generation, and it isn't close (I worked in wind turbine design for a number of years). Everything about that video just screams that they have no idea about modern wind turbine design though. Maximizing efficiency and output is all about going big, so contrary to their claim at 42s in that video that a standard turbine spins 800rpm, a typical onshore wind turbine with 50-75m blades spins more like 11-13 RPM. Generally the more powerful they are, the slower they go too, since you want to keep a fairly constant tip speed (usually ~75-90m/s) and more power means a larger turbine.
Next, I'm confused why they have what look like repurposed fans or blowers as their turbines. The dense mesh around the blades is going to kill their efficiency, since it's obstructing a lot of flow and it's also going to cause a ton of turbulence. There's a reason why all actual professional wind turbine designs are completely out in the open air. Their blade design is awful too. They also don't show any power measurements, and I get the feeling they aren't even applying a load, but rather they're just letting them spin freely. Electric generators have more resistance when they're actually, well, generating, so freewheeling tests tell you very little. That having been said, I'm sure their concentrator does better than their other one, but they're both awful.
Also, again, I didn't say it doesn't increase the output to add a concentrator or duct, I said it's generally not worth the expense, materials, cost, and structure, since you'll get a greater increase in output by just making the rotor bigger. For the same amount of materials and cost as the concentrator, you could just make the blades on the other one twice as long, and you get far more energy that way.
For some evidence that I know what I'm talking about,
here is a turbine I did some design work on (I was in the blade design department). I guarantee you that it's vastly more efficient and powerful than anything in that video above.
Also, interestingly, efficiency isn't even necessarily what you want. The maximum theoretical efficiency of a wind turbine is around 59%, and we can actually get darn close to that, but it turns out that if you back that off to 45-50% instead, it substantially reduces the loads on the blades, which then enables you to make the blades longer for the same strength and actually makes more power than you would get with the smaller, higher efficiency design (with no more structural load). At the end of the day, the most important thing isn't efficiency, it's annual energy production, cost per kWh, and capacity factor.
(There's also considerations about where the turbines will be installed, what kind of conditions it'll need to endure, what storms you want it to handle, etc, but this post is getting long enough already)
