Emails being ignored by University
Is there something about the American system that makes people not reply to their emails?


I've spent my education and career in the American system (including California) and haven't had any particular problems with people being unresponsive to emails.  This is probably specific to your institution and/or the individuals involved.

That said, in your academic life you will certainly encounter more people who don't respond to your emails, so you need to be comfortable with other forms of communication, and to have strategies to handle such cases:


Call by telephone
Visit in person
Talk to an administrative assistant
Find another person who can help with your issue
Escalate to a superior
Ask a colleague if there is a particular reason why the person might be unreachable (e.g. sabbatical, leave of absence, vacation, has quit, medical problem, is dead, etc)


And as mentioned above by Anyon, it is also an important skill to write emails that minimize the effort needed for the recipient to read, comprehend, and respond.  This also will improve your chances of a useful response.