A lot of the complexity of lisp and scheme compared to tcl is effectively managed by the dynamic typing of the language, so that it DWIMs nicely. I definitely appreciate having specific points called out. My conclusion is, they simply didn't learn the rules. By which I don't mean that they tried and failed to learn the rules, but that they didn't spend time learning the rules in the first place. Granted, I don't have statistics and controled studies to back up this contention.
Similar things are true of the other cases above.
RMS proposes to have two languages, both of which scale all the way from simple users to the most complicated cases. Tcl advocates propose to have two languages, one of which concentrates on power and functionality, the other on being lexically inconspicuous glue with a shallow learning curve.