In a world where everything esle is changing, it's reassuring to see Telstra and Optus once again launching legal salvos at each other.

In the latest clash, Telstra has hauled Optus into court to complain about its allegedly misleading ads.

Telstra takes exception to the tagline "covering more of Australia than ever before."

Most of us might think that Optus is merely referring to its own network, but Telstra argues that Optus is claiming bragging rights over all networks now and in the past.

It's understandable that coverage should be a big deal in the world's fourth most sparsely populated country.

But isn't it a little old school to be arguing about it now? Not just because, according to official figures, Telstra covers 99.5% of the population, with Optus a whole one percentage point behind.

It's because the whole industry is racing to 5G, and yet somehow these two see 4G coverage as a critical differentiation.

Most operators want their users to get excited about, and start thinking about, the 5G use cases – cloud gaming and AR, ultra-low latency, precision synchronization, network slicing and the rest. But evidently not these two.

Their counterparts in neighboring markets are finding ways to collaborate on 5G coverage because they see it as, a) a cost and b) not a factor of differentiation.

At least Optus has shown it is open to collaboration, telling a parliamentary inquiry into 5G last November that it would like to see further study of the "barriers that limit the effective adoption" of network sharing.

By contrast, the national industry body AMTA, which includes both operators and the leading vendors, acknowledged that passive sharing of ducts and tower sites was well-established. It went on to say:

"However, sharing active infrastructure such as electronics including radio transmitters and antennas, has a range of technical and economic constraints that make it generally not feasible to share."

Sadly, this important revelation has come too late for China Telecom and China Unicom, who have already deployed 200,000 basestations in a shared 5G network.

Yes, it helps a great deal that these two telcos have contiguous 3.5GHz spectrum; it's almost as though somebody had been thinking about this in advance.

Besides the Telecom-Unicom arrangement, all Chinese 5G operators are party to a small cell sharing deal.

Outside China, South Korean operators have just struck an agreement to share 5G basestations in smaller rural areas, KDDI and Softbank have set up a network sharing joint venture for rural Japan, and some Taiwan operators are also reported to be weighing sharing deals.

Coverage ranks low on the hierarchy of 5G needs. Operators are on a road to nowhere if they tip billions into the new network without changing their thinking.

— Robert Clark, contributing editor, special to Light Reading