It really doesn't. I'm an experienced front-end coder, and I can tell you right now that the amount of extra work I put into IE6 support is really not prohibitively high. The bugs and issues in IE6 are well-known and well-documented, so it's a simple matter of professionalism to be aware of these things, and account for them, as you code.
Depends on what your frontend looks like. The average run-off-the-mill HTML site can ofcourse be made to work in all browsers with little effort. The real pain starts when you want to do interesting stuff. Advanced AJAX and javascript magic just doesn't work in IE6 without horrible overhead - partly due to the lack of sensible debugging tools.
Well, frameworks go a long way but they don't help with the pains in the CSS area. When supporting IE6 you're generally limiting yourself to the capabilities of that browser. And for any non-trivial site you will run into hard problems regularly, unless you're leaving HTML behind entirely (ExtJS, Flash).