[hutzlibu]

Yes they can, if they have the time and skills to port it to the many plattforms desired. But maybe you do see the point, that it is a bit easier to develope and test for only one plattform, as opposed to ... many?

(have you ever released something cross plattform?)

Point being, the web is a plattform now (since quite a while) and not anymore a static site displayer. Provide a technologically better alternative and people will use that.