About that b). It‘s less about internet speed and more about your CPU not being fast enough to render everyhting in a useful time. With all that lazy loading, the browser is stuck with rendering for a couple of seconds - for each page...
This is why the browser isn't the best place for things like this. A Fat client is better. I still don't understand the push for webapps, when we have all this hp, storage is cheap, and we have modern installers that don't splat everywhere.
The browser is perfectly capable of stuff like project management workflow apps when you’re not shipping 22MB of useless abstraction layers in a runtime language.