Tcl and Tk are very nice systems, which were done in by bad marketing and leadership.

See this article:

http://antirez.com/articoli/tclmisunderstood.html

It also looks ugly by default.

Yes, "bad marketing". It's been possible for years to significantly improve the look and feel at the scripting level, but they never bothered. Also, the fact that it took them so long to figure out that Gnome and KDE were where Unix was headed and get with the times is not a good sign that they have the marketing skills necessary to stay current.