It's not as good as a native app, but Sony could and probably will release a web app. On that note, does streaming stop if you leave Safari?
I was thinking about this as Apple is moving to extort their 30% from companies but then realized they would just change their TOS to block websites or something else equally stupid. I also don't think websites can get access to the run in background services and if they can now, I'm sure that will get removed.
I used to think it was far fetched that Apple would eventually try to get 30% from every app for sale for OSX, but now I'm not so sure. The app store is their beachhead and I'm almost certain that one day in the future they will lock out apps not sold through the app store.