There is a proposed standard, ARC, that would allow mail receivers to
do more intelligent whitelisting. It's not ready yet.
There is a third option --- which is that if you want to participate on
certain
mailing lists, you have to use a non-DMARC e-mail address. There are people
with google.com addresses that need to use non-Google addresses in order to
participate on the Linux Kernel Mailing List.
I've seen comments that people who were on Yahoo can fortunately go to Gmail.
What happens when Gmail publishes a p=reject like they said they were going to
(even if the timeline is delayed), per
https://wordtothewise.com/2015/10/dmarc-news-gmail-preject-and-arc/?
Perhaps people can go to Outlook.com? What happens if they go to DMARC
p=reject? Everyone can go an sign up for yet another domain?
That just kicks the can down the road, but eventually that can will take no
more kicks.