There are plenty of Photoshop-inspired apps that run in the browser already. None of them are on par with Photoshop obviously, and maybe none will be in 5 years but I don't think it's completely unrealistic.
There are a bunch of obvious advantages to webapps like no installation, settings are kept no matter which computer you are working from, works everywhere, etc. They may not outweigh the disadvantages in your view but it does seem to be the trend in the world.
I think we both agree that the technologies will soon be there that enable native performance (not to mention the JVM) but I still can't see the advantage with the exception of freeing the user to run an installer, but caching assets will still be a requirement. The ability to keep settings persistent can be addressed with a traditional model in the same way as Abode Creative Cloud or the Steam client, that is to say just store them. The run from every machine claim is incorrect because engineers must tune and verify that the programs run in each browser, in much the same way as is required by conventional C++ programs. In fact, the myriads of browser, version, architecture combinations make me remember the good old days of targeting x86 Windows XP.
I think the trend is very much only applicable to service startups, and against it run trends like C++11 and QT letting me build native apps on Windows and Android from the same codebase.
Do you think it's technically possible to get something on the level of Photoshop with performance that is, at least, acceptable enough, in the browser? Using asm.js I suppose?
I don't see why not. I won't make any guesses about a timeline, but it seems inevitable to me that it will happen at some point or another. Current technologies allow you to do quite a bit locally and it might even make sense to offload heavy expensive operations to a server instead.
Ah, sorry, I meant to ask if you think it's currently possible with asm perhaps, considering that we can already do quite a bit of heavy stuff in js right now. I have no doubt over time it will be doable, I'm just curious if we might already be there (purely technically, of course, I can imagine we might not have the right tools to actually pull it off right now).
There are a bunch of obvious advantages to webapps like no installation, settings are kept no matter which computer you are working from, works everywhere, etc. They may not outweigh the disadvantages in your view but it does seem to be the trend in the world.