Free Web Tools vs. Expensive Online Learning Platforms

My district spends what is probably a LOT of money on AngelWeb, which is an online learning platform.  Lots of my colleagues adore it.  You can use it for quizzes, polls, discussion boards, blogs, bookmarks, etc.  I keep going to trainings, keep thinking about using it... and keep not doing it.

Why?

So far, AngelWeb doesn't do those things as well as the free tools I'm already using.

I use Wordpress as my class hub.  I can do polls there, or use PollEverywhere during class.

Posterous provides password-protected blogs with personalized themes, and UNBELIEVABLY easy addition of media content.  I'll be using it for e-portfolios next year.

Edmodo gives me a private Facebook-like messaging space that I can use for discussions.  I can also set up a "fun" group for the  "Hey what's up?" chatter.

Diigo provides an easy way for me to do bookmarks.  AngelWeb doesn't let me use tags, and with 300+ bookmarks and counting, I need them!  With Diigo, my students can also post and annotate links to my class account, which I'll be taking advantage of this year.

Google Docs is my weapon of choice for class files.  I'm having a little trouble with students not being able to access public files from some browsers, but I have a "dummy" Google account for kids whose parents are concerned about having them set up their own.

The main area where AngelWeb would come in really handy (and the main reason my colleagues like it) is giving quizzes and tests.  You can maintain a huge question bank so that every kid has a different test.  That's not something I really need.  If I want to do an online quiz, I can use Google Forms. (It's not self-grading, but again, that's not something I need.)

Sure, it's a pain to maintain a bunch of different accounts, and it has taken time for me to introduce and implement these in class, but the extra functionality is worth it.

So why is it that these free tools look better, are easier to manage, and are easier for students to use than the Very Expensive systems so many districts pay for?