Apple iOS 15 launching in September 2021 will allow users to turn off email open tracking (plus hide IP addresses, and hide their email address)

Has anyone started to think about workarounds for their "Open" tracking and automation usage?

I have generally used 'Email Open' for marketable person lists, success, email attribution, sales alerts, and to trigger nurture-stream transitions, etc. …

Are y’all switching triggers from “Opens Email” to “Clicks Link in Email” and dealing with the success rate drop-off? What other options exist? Marketo has an FAQ on impacts (below) but it doesn’t really mention the triggers other than to reduce dependency on it … 

More info: https://www.omnisend.com/blog/apple-ios-15-update-email-marketing/

Maketo FAQ: https://nation.marketo.com/t5/product-documents/apple-ios-15-privacy-announcement-how-marketo-engage-could-be/ta-p/314401