I don't even know if this is a bad thing - engaged developers want to work with what's new and exciting, especially early in their careers. Using a "fresh" stack is a means of targeting those devs and wooing them to your company.
I also believe there is a very viable long-term strategy of choosing a few of the current "hotness" stacks over your early career and learning them thoroughly. When the time comes that you're not wanting to chase the new thing so much and you start to experience age-related discrimination, you can focus on maintaining and improving existing projects written in those "old" stacks. There are lots of people out there today making good money doing "unsexy" work like maintaining Java/JSP or ASP Classic apps. In ten or twenty years, those jobs will be maintaining Rails, Django, and Laravel apps.
It is not bad thing, it is just how things are, and I suppose it drives progress in the long term. Younger generations picking up slightly different sets of tools, with different tradeoffs and features. This relatively chaotic movement turns into evolution as some of the ideas stick and get reinforced, and that evolution hopefully will create progress. Of course all this takes long time and in the meanwhile we might see both major misteps, and moments of brillance that nevertheless for some random reason get forgotten and buried.
I also believe there is a very viable long-term strategy of choosing a few of the current "hotness" stacks over your early career and learning them thoroughly. When the time comes that you're not wanting to chase the new thing so much and you start to experience age-related discrimination, you can focus on maintaining and improving existing projects written in those "old" stacks. There are lots of people out there today making good money doing "unsexy" work like maintaining Java/JSP or ASP Classic apps. In ten or twenty years, those jobs will be maintaining Rails, Django, and Laravel apps.