Open Source needs to be used first. Do you want to rely on websites implementing something like spell-checking? In your native language? I don't. I want common

Open Source needs to be used first. Do you want to rely on websites implementing something like spell-checking? In your native language? I don't. I want common problems to be solved in the browser and I want to have some reasonable control over my browsing experience and some consistency - something SPAs actively undermine. How are SPAs different from Flash? Sure, you have some remnants of standard HTML there, but with canvas, local storage and JS compilers, those two technologies look remarkably similar both in terms of advantages and problems. You get a blob of non-semantic, imperative code that does non-standard things. The funny thing is, many of the stated advantages of SPAs can be easily implemented in document-based web apps. A lot of the repetitive info could easily be removed with proper caching, and it would be even more efficient with cacheable client-side includes. Not only it would be roughly as efficient, it would require much less work to implement.