Users may not switch (right away) but how we as a community talk about this problem can switch. This will ultimately help the problem get fixed when perceptions shift, either within Google or by new users evaluating other options given Google’s reputation of poor deliverability/interoperability.

Also I suspect a lot of Google’s early adopters will be switching away due to this change. These are the tech-savvy evangelists who helped build Google Apps to what it is, and can plausibly do it for another service too.