I don't think the user experience of Web apps has to be worse than native, but even if we grant that it's worse, I'll take it over the pain of installing apps. And, based on the experiences of numerous SaaS companies, I'm far from alone in this. A lot of native app developers wail and gnash their teeth about how the Web is a technically inferior solution (which, again, I disagree with, but let's leave that aside). But, from my point of view, native apps on the mainstream desktop platforms have consistently failed to get deployment right, and that's terribly important to users in practice.
Take, say, LibreOffice. Is it better than Google Docs? Sure, probably. But I have such basic needs in word processing and spreadsheets that the marginally better user experience of the native app doesn't make up for the added annoyance of downloading LibreOffice and keeping it up to date. All indications are that most users are like me.
