ios 13 save mail to dropbox

According to my research, this was never possible. You could certainly copy a message and save it as a file, which you could then send to your dropbox account, but forwarding a mail message to dropbox from what I can find was never an option.

As to why not, you'd need to ask Dropbox. Dropbox is not an Apple Product. Dropbox is a service which saves documents, files, photos. Email messages are not files.

Are you asking about the actual email message or an attachment inside an email message. From my research, I can't find that it was previously possible to save an email to dropbox, but it is and has been possible to save an attachment inside an email message to dropbox.