you're not complaining about "design trends", you're complaining about capitalism.
everything is touchscreen because it's cheaper than mechanical buttons.
all products looks the same because 1. it's cheaper 2. mass appeal is more profitable than niche, and 3. it's risk free
everything's an app because they can collect data, push notifications, and force you into closed ecosystems.
laptops are thin because they probably sell more as a lot of people prioritize lightweight and less bulky laptops to carry them around easier. phones are going the other way but when you're talking laptops it's kilograms rather than grams so the difference is more important.
finally rounded corners are probably a design trend, although i am generally in favor of them.