Outlook 365 Email Reminders Not Supported by non-Microsoft Email Accounts (e.g. Gmail)

I worked with a Microsoft Tech Support Specialist for nearly an hour this morning troubleshooting why, in Outlook 365, the follow-up flag can only be toggled on/off and a follow-up date and reminder is not available. When we switched between an IMAP enabled Gmail and a hotmail account we discovered the ability to set a follow-up date and/or reminder is limited to Microsoft based email services only. It would be excellent if this capability could be embedded into any valid email account service which Outlook 365 supports.