I don't believe people actually want "new and trendy". It just happens that nobody is giving them what they need, so they have no choice but to find the new "hot" thing. Because social networks are so disconnected and fragmented at the moment, it only makes sense for people to use social networks that others use, and that's why we see trends.
Most consumers are satisfied with "the Internet", and as far as I know, not many are looking for alternatives. Most people use Google, they don't change their search engine every few months. People in the US speak English, and I don't see many people learn other languages based on trends.
In a world of apps, where people can't think in any other way, sure the gimmicky app is going to win. They know that they will never find what they need, why not having fun doing so? With a slightly different mindsets, one in which you realize that there's no point in having so many apps, you think differently and your values change. People will find diversity in content, not containers.
Are all businesses writing their own crappy internal management systems because it's trendy? Are banks spending millions to build a crappy banking system that's more or less a clone of any other bank's for fun? Are the millions of different "User" classes programmed by people who thought theirs was better/cooler?
Society has taught people to think wrong. Instead of thinking about what they need, they go straight to thinking about how they need it. Then, once they're offered a solution that does exactly what they need, they reject it because it doesn't match the solution they imagined. And we're talking about people that can't think of a solution themselves, and can only pick examples from their past. We're in a world where people ask "I want to buy an iPad from Amazon.com" instead of asking "I want an iPad", or better "I want to browse the web and watch movies in my bed".
That said, I would still like to understand why you believe that people want toys and trendy. Is it a symptom of something else, or are these features intrinsically valuable to them?