It's not just publishers. My current org uses SalesForce and it's frustratingly slow. Opening a single record takes several seconds as every single interface element is generated dynamically and then populated, seemingly one at a time.

When it's finally done loading, you click on a dropdown, and then the dropdown just shows you a loading spinner, as your client asks the server what should be populated in the dropdown menu. And of course it takes another second. Clicking virtually anything, including back (which should be instantaneous on a proper webapp), will present you with yet another loading spinner and a multi-second delay.

I understand the benefits of building webapps this way, but the benefits primarily accrue to the developers of the app and not to the customer.