I disagree that coolness of tech has any relation at all to job security. You're implying pure tech companies will always use cool tech. But there are plenty of

I disagree that coolness of tech has any relation at all to job security. You're implying pure tech companies will always use cool tech. But there are plenty of pure tech companies outside of major cities that primarily use PHP and Rails and Django and ASP.NET and Perl and JQuery and maybe colo servers and haven't seriously changed their stack in 5-10 years if not longer.