What's sad is that it looks great on his or her resume to do that. That developer might leave a trail of carnage but they don't care--on to the new shiny job for them. It never catches up.

I can't really blame developers for this -- they're just responding to incentives. So long as hiring managers penalize candidates that don't have experience with trendy stacks then your actively doing your employees a disservice by prohibiting them. The only thing I can perosnally do to combat this problem is be conscious of it, not engage in that kind of hiring behavior in my office, and hope that the culture changes.

Giving employees opportunities for side projects helps somewhat. Allowing for gradual migrations to new technologies helps as well.

100% this is a huge flaw in our industry, it applies at the highest level (CTO, architect) too.

In a friend's company, their CTO has mandated a rewrite of the backend in Clojure, and that it should be as asynchronous as possible.

Low and behold, the devs aren't familiar with the language, and the async has resulted in a host of heisenbugs, that are hard to reproduce.

On the CTOs resume though, he would show how he got the shiny new architecture rewrite, any problems were the devs fault.

While I agree with you, who is in control there? Who lets the developer pick the tech and leave a trail of carnage?

Neomaniacs gonna succumb to neomania. The bigger question is why the system permits that, rather than steer those urges to try something new into useful experiments that might advance the status quo.

Resume driven development.