Call me old fashioned. But, i don't understand what is the big deal about zero trust. Isn't the principle of least privilege was what security was all about for last 20 years? We had VLANs since the dark ages. Then vendors sold us micro-segmentation as the next big thing. Now with zero trust they seem to be saying lets do VPN everywhere and have a firewall between everything. Just for fun, lets use TLS instead of IPSec and it'll solve all our problems. You just need to buy fifty more boxes from us and life will be better.
Don't get me wrong. I'm in complete agreement with using identity as the new perimeter. I highly recommend reading Google BeyondCorp papers. They are well written. We moved everything to Okta years ago and we've been very happy with it. But, I'm very unhappy with what security vendors are selling us. They seem to be completely missing the point.