The problem is that with templatemonster and many of those template places, lazy webmasters, and people with little HTML experience simply download the template and throw content. It doesnt work that way, unless you have the exact same # of lines of text, etc. So most of the times a template is used, unless its 100% recoded, it wont look right.
(We do about 4-5 sites using templates a week, from templatemonster, we never had 1 template that we could use as it came. The html work is horrible. Those artists that do the sites are very good at graphics, but suck at HTML. Or maybe they did the Graphics -> HTML functions of photoshop which makes the slopiest html code you can imagine ;b)