Experimenting is good. I do it all the time. Just take a look at my repos on Github. Just a few of them are conceptually (and arguably) "new", while the others are just exercises to learn about new things. Experimenting about things, even about the basic ones, helps me a lot in my learning process. At a personal level.

But when you watch the bigger picture, with companies actually building software for clients that trust them, then choosing technology is a delicate, non-trivial matter. It's important, and I mean in actual dollars (or euros). There is where the expertise of older developers, people who have founded, sold or shut down profitable and unprofitable companies, who have worked in a gazilion of projects and made a lot of expensive mistakes, there is where that expertise comes to play. They can enlighten the sometimes childish, faction-like debates about technology that keep repeating themselves over and over. That can free us to think about new problems and new things, based on past experience. That's how science advances, and that's how software development advances too, in my opinion.