(This is a joke patterned off the "Patches welcome!" response common in the OSS community, but it's also very serious: high quality web development tutorials do not spring into existence from the ether. You can either write them, pay directly for them, or hope that someone subsidizes their creation. Hoping for subsidy will tend to result in less tutorials being written than the market would prefer to exist.)
Why? There's plenty of successful pro screencasters: RailsCasts, PeepCode, Destroy all Software, etc. Some have free content, like RailsCasts and Ruby Tapas.
Producing a decent 15 minute screencast takes hours of preparation. At decent billable rates, that means hundreds of dollars per episode. Plus these are videos with real value, that if they do their job, allowing the watcher to earn tens of thousands of dollars more per year.
As for free tutorials, you're a Google search away an essentially limitless library (many of which were written by some of the screencasters that make you sick). I've learned from free material, but I also feel that that an on-point screencast is worth a few dollars. That's why I'm more than happy to pay for RailsCast, Tapas, CodeSchool, and more, every month.
As for "should be free", I really don't know where you get this. In a world where information is a scarce resource, perhaps. That's not the world we live in, and I hope all that can add value all the best in selling their expertise.
Thanks bdcraven, we completely agree. Even before the rise in screencast popularity, writing a good book on programming took just as much effort, if not more. Authors certainly didn't give those away for free either.
Epa, thanks for the feedback. We are in full support of the fact that web development tutorials need to be open and easily accessible to all. And around half of the content on our site is completely free. Most quality content, however, takes a very big time investment to produce properly, and it is often impossible to recuperate that investment through advertising revenue alone. The process is anything but easy, quick, or cheap (http://www.backbonerails.com/blog/how-to-create-compelling-t...).
Take Ryan Bates for example, I would be hard-pressed to find a good Rails developer who hasn't picked up a thing or two from Railscasts. And $9/month is nothing compared to the wealth of knowledge one can get for that price. We simply want to enable more developers like Ryan to produce quality educational content and monetize it, if they so wish, on Bitcast.
When I was a kid learning to code, there were no screencasts. There was documentation and tutorials. All of which still exists, and honestly, is much better than when I started learning. There are also lots of "teach kids to code for free" sites, and places to find mentors or groups. Again, non existent when I started.