As om_prakash said, many more web sites are integrating support for many browsers, not only IE and Netscape (although those are probably the more popular ones).
Also, DHTML will probably become much more advanced and compatable (i.e. no browser detecting!) with the release of the next versions of the popular browsers (IE, Netscape, Opera, Mozilla) with more integration of CSS2 and the beginnings of CSS3 standards, including read aloud, border radius, advanced text effects and more filters and transparency settings.
It's kind of silly: IE and Netscape are more popular than the others, but the others support more DHTML in many areas.
And do people really use it? Links that add their site to your favorites, dynamic pop-up menus, form validators, snowflakes falling down your screen -- these are all DHTML, and many are quite popular.