That's an interesting observation, and it matches with my experience, too. Specially in larger teams, the senior developers gravitate towards the back-end, and the 'full-stack developer' is an extremely rare sight.
If I had to guess why it is, I'd say that back-end technologies naturally evolve slower. Yes, we are in the middle of a Big Data boom, but even then, the rate at which Hadoop changes is nowhere near Ruby on Rails, to cite two popular technologies.
(oldster here, mostly doing 'back end' type stuff) -- I think it's due to the fact that younger folk are usually more comfy with the GUI aspects of the latest tech. Me and my 40+ prog friends generally hate all the newest webby mobile stuff, we like email and IRC and text documents and command shells. We generally despise Twitter, FB, anything that enforces a 'modern' GUI experience on us.
Also, the back-end stuff tends to be a bit less sexy, but also less fault-tolerant. Management sees the front end; the back end is basically magic. So it makes sense that you have Gandalf back there with his beard and recumbent bike banging out magical koans to keep the database alive, while young bucks guard the front gate of the castle.
Yes and no. The front-end (as far as web goes) is still HTML and Javascript, just better frameworks. And the base patterns of good design still apply regardless of the front-end technology.
The back-end in the last five years or so has definitely had a lot of change in data stores, emphasis on RESTful API exposure to front-end and other back-end services, web server choice and style (WSGI, PSGI, FCGI, etc).
The biggest difference is that a front-end developer has to worry about the performance of a single client using a single state machine. The back-end guy has to deal with making a site fast and reliable while supporting 100s or 1000s of those clients concurrently.
Crash the browser every 100K views and someone reloads. Crash the back-end every 100K views and someone gets fired.
I'd say that the new API-centric model works very well here. The old codger has complete control on what's coming and going from the core application, without worrying about a whippersnapper messing with the DAOs and adding a bobby tables vulnerability.
In the Dark Past, this last line of defense was in stored procedures, but we -- 30-something greybeards :) -- know what a mess that was. There are plenty of companies who are still tied to an ancient DBMS due to that 10kLOC stored procedure that looked like a good idea at the time.
> If I had to guess why it is, I'd say that back-end technologies naturally evolve slower.
I think it is this way because back-end development requires more expertise than GUI development. Steady more experienced developers are better suited than new hires.
The front-end guy also deals with the users more. And after spending 20+ years doing that, us older geeks are more than happy to moved to management or the back-end. Peace and quite.
I know what you were meaning to say but I have actually been chastised by many a frontend dev for saying "Oh, all the stuff the frontend team does is easy".
In either area (frontend / backend) the complexity depends entirely on the problem that you are trying to solve and I am sure there are plenty of FE problems that require a high level of expertise to solve elegantly.
If I had to guess why it is, I'd say that back-end technologies naturally evolve slower. Yes, we are in the middle of a Big Data boom, but even then, the rate at which Hadoop changes is nowhere near Ruby on Rails, to cite two popular technologies.