About applying progressive enhancement to html5

Progressive enhancement in modern web development is the process in which you rely on some basic technology, supported by all major browsers, for all the functionality, and add fancy technologies only to improve the experience for those users, who use the most advanced and up-to-date browsers. Unobtrusive JavaScript is closely related to progressive enhancement. You do not rely on JavaScript for important functionality (redirecting between pages, submitting forms, ajax without alternative), but instead use it only to make the application easier and more comfortable to use.
But can we apply progressive enhancement to html5? An interesting article on how we are forced to apply some fixes when building layouts with html5 and that is certainly not progressive enhancement.
More details on progressive enhancement can be found in the Understanding Progressive Enhancement on A List Apart.