Denmark and Canada required the implementation of DMARC for government entities earlier this year.
There are also reports that by the end of 2019 there were close 2 million domains that have implemented DMARC, which is great. I’m sure by now, the number has probably hit 2 million or gone over. DMARC Policies Increase 300% over 2019 – dmarc.org
BIMI and ARC are starting to become a focus now as well. BIMI most likely will help to drive the adoption of DMARC, but time will tell.
ARC is more for those that have mailing lists and mail forwards. It is not required for everyone to use or implement to help with email authentication.