I wouldn't associate those mainly with corporate networks. The prevalence of RFC1918 use is an artifact of IPv4 and address shortage. IPv6 usage is already at 4

I wouldn't associate those mainly with corporate networks. The prevalence of RFC1918 use is an artifact of IPv4 and address shortage. IPv6 usage is already at 40% today. Also hosts are increasingly multihomed, devices are likely tohave 2-3 network interfaces, with v4/v6 addresses for each. VPNs are run in "split tunnel" mode where some traffic goes via VPN and some not, so both un-tunneled and tunneled traffic is allowed simultaneously, etc.