Here are few points I can think off on top of my head
Lack of Specialization
The industry no longer demands a specialization in fields. There are tons of average mid tier companies who want a developer who can build an average product and deliver. They don’t build ground breaking software, and hence don’t need a specialist.
Volatility of Web
The web has tremendously grown, primarily because of JavaScript language has turned into a full blown sharpen weapon from a mere knife. But this has also caused a lot of volatility and ephemeral language paradigms. Every year a new framework is trending in each stack of HTML / CSS / JS. How can you have a specialist of something when things are changing rapidly!
Startups Make it worse!
For example, I am the founder of Average Joe Software Inc. I want to build my prototype, of course I need it done quick and dirty and want to minimize my cost. Instead of hiring one guy of DB, freelancing UI, hiring software developer and a deployment guy. It would be easy if I can get everything in one packaged in one person. I wouldn’t care if he is a specialist, because he is cost-effective. That’s what matters! With more and more people becoming entrepreneurial startups have flooded the career sites with this new disease of lack of specialization and packaged it as “Full Stack Web”
BootCamps took the business opportunity
Now that the career sites are flooded, boot camps are a huge success since industry no longer needs specialization/expertise. Boot camps churn out thousands of web developers with basic knowledge of front end development and little knowledge of backend and database. And provide “Full Stack Developers” that industry craves for..
Overall I think it is a trend and nothing more. categorize us, name us, group us but the essentially we just Software Developers with different languages.
A developer who is confident to solve problems in stack that is unknown to him is Full Stack Developer.
Originally Written on Quora.