> Isn't the disadvantage of SPAs that you are unable to link to / share a specific piece of content?

Actually, this is achievable with push states, so isn't a strong argument against single page apps.

I think the problem with SPAs is that they exacerbate memory leaks, since they don't have the typical 'reset' of a browser page load to clear them. Also, a lot of SPAs re-implement browser functionality like scrollbars and the back button without proper cross-browser testing - let alone usability testing.

Conceptually, there's nothing wrong with SPAs, but many of the implementations are shoddy at best with no clear advantage gained.