After working in the web development industry for the last 6 years or so, dealing with older browsers that lack decent support for CSS and Javascript is something I face and deal with on a near-daily basis. Why near-daily? Well, I do a lot of Server side development which tends to be browser agnostic.
Dealing with older browsers is a problem that MUST be solved, or handled, one way or the other. Some solutions are more involved than others and some solutions will not be accessible under certain situations. One option that I think gets ignored all too often, is the possibility that older browsers simply get a different experience, visually and behaviorally.