Mass emails often hard to read on a mobile. Where’s the proximity thinking?

It’s amazing that the people who design mass emails don’t consider that many of those emails will be read on mobile phones. Things like newsletters, gallery announcements, sales promotions, and other emails sent simultaneously to many people usually don’t have designs that respond the type of device that they are read on. Worse yet, they often have a lot of text on each line, so even if you rotate to portrait view, you still have trouble reading them. Where’s the proximity thinking?