I don't see any of those as "unless ifs", but "whens". Gaming will come to the browser, first with HTML5 and NaCl. Offline access isn't a technical issue, we're just waiting on developers to implement when they feel it's necessary. JS is only getting faster and, combined with efforts like NaCl, we'll have native perf inside 5 years. Printing from my Cr-48 is already solved (Cloud Print is great), and we'll undoubtedly see scanning and camera solutions soon, one way or another. Native tablet apps will be killed by web apps in the same way native desktop apps were/are being.