The reason people don't read email is that companies have poisoned their communication channels. If an important email is right beside a practically junk message, it will be lost.

90% of the work emails I received were indistinguishable from spam. And they were sent by my employer.

“Did you know HR has an XYZ workshop” or “Look at what your coworkers are saying on Internal Company Social Network” (that I never once logged into). Literal spam. It’s no wonder I became completely desensitized to email notifications from my own employer’s domain.

An interesting aspect of this: Where I work, an email subject line including "important" or "urgent" is a 99% indication for junk...