Originally Posted by Marvin
I don't think so. The NaCl feature in Chrome OS helps bring web technology closer to native but Mozilla is against that because it tries to put proprietary code onto the web just like ActiveX and Flash did. The open source nature of the technology makes it better but still limited. Bytecode can be reverse engineered so not good for valuable software.
When you do something like video editing, you can easily have 20GB+ of footage. Unless you give your browser filesystem access, you can't edit that footage. Same goes for photography. Not everyone wants to upload their personal files onto a server either regardless of how much they trust the company running the server.
When it comes to games, something with low amounts of geometry, low res textures and repeated textures is viable but take the recent Tomb Raider game. It's about an 8-9GB download because of all the levels, textures, character models, audio, game engine etc. Games can be streamed easily now so that's an option but web platforms take away the ability to play natively.
No matter how good a web platform becomes, you will always be able to do more with a full operating system so why choose a limited platform? The only reason to go with the limited platform is for limited hardware or because it's a limited-use device like an iPod Nano.
A limited platform has many advantages - ease of maintenance and updating, security, and speed. Chrome OS is a great example, it's proven to be pretty much unhackable.
For developers concerned about proprietary code, a trick many web developers use is to keep the application logic on the server, and simply pass messages to the browser client. Piracy is a problem with compiled binaries, in many ways web services are better, especially if you're smart about things.
Your video editing example is a good one, but I've seen web apps which allow you to interact with local files without uploading them (a fun 'DJ' app I have on Chrome for example).
I won't argue that web platforms are *there*, yet, but they will be, in the not too distant future.