Still an ongoing issue, same excuse management is considering this and will come back with an answer, last time I heard this same statement it was fours years later and still no answer, also 2020 5G same thing and I'm guessing another 4 years for a NO answer. Please can someone please let us know if I can simply purchase one like at Telstra or just unlock it so I can go on doing my business.
Yes, I was not sure if you meant external Static IP or Internal Static IP and I think I have this right but happy to be informed otherwise. These comments relate to modems and not mobile handsets.
If external, then CG NAT is the reason and its implementation is related to lack of IP Addresses. There are limited IP V4 addresses left and whilst most devices are dual stacked for IP V4 and IP V6, the industry is not in a hurry to transition to a full IP V6 only world where NAT is not required without other control mechanisms being in place for residential users. Sometime in the distant future, your IP V6 IP address will become your unique ID and you won't need to hide behind the modem or router's NAT - opens up a whole new topic of security. Some carriers are making the transition to IP V6 under protected mechanisms e.g. Telstra NBN dual WAN modems use 4G VoLTE SIMs for Voice and Data Backup only when NBN is down - they use IPV6 for that function in a limited time period i.e. only when the NBN is down. Optus like most carriers, uses modems that are dual stacked to connect to general Internet Servers that use both schemes.
From my readings, Optus uses Carrier Grade NAT (CG NAT) on their 4 G and 5G Mobile Broadband Services and these are in full time deployment for 4G/5G mode operation , unlike Telstra NBN modems which will use IPV6 in Back Up, not IPv4 in BackUp, and for general NBN service use Dual Stack IPv4 and IPv6. Sometimes an IPV6 enabled ON setting can cause havoc in land connected NBN WAN services with cloud server Applications that don't handle IP v4/IP v6 conversions well and this is resolved by turning IP v6 OFF.
Some ISPs who don't have enough IP v4 addresses also use CG NAT for their land connected NBN services - they have to buy them off organisations who don't need them which can be surprisingly costly.
Unlike a traditionally carrier assigned network for external IP addresses which are generally allocated for a 24 hour lease and then refreshed, CG NAT is allocated dynamically on demand allowing the address to be shared between multiple different users during the day - that is why its use is generally mutually exclusive with a Fixed Network or Static External IP.
If internal static IP address, the last post I read about that it was in possible future firmware development and like most readers, I am surprised about its omission from the launch version of the modem.