This week the leaders of Cisco Systems and Ericsson, two of the largest networking companies on Earth, announced one of the largest non-mergers in history.

Question of the week: Why didn't they just merge?

I'll have an answer in a moment, but first let's look at some of the details, as they were discussed on Wednesday's analyst call with the companies.

The two companies, which account for $75 billion in revenue between them, described the deal as a "broad strategic partnership" that involves co-marketing and sales of products, integration of products and services organizations, and co-licensing of intellectual property. In addition to the large sums of cash involved, Ericsson and Cisco said together they will reach 180 countries, have a combined portfolio of 56,000 patents, and integrate 76,000 service employees. The two companies stated that a financial target has been pinned to the agreement: $1 billion in revenue growth for each.

Ericsson will start selling Cisco's routers and networking products immediately. The deal also includes technology integration in some specific areas: Cisco and Ericsson will jointly work on a network architecture for cloud and 5G technology, as well as the Internet of Things — a broad area that the two companies like to wrap around smart-city initiatives. A broad patent co-licensing program is planned, though the details have not yet been released. That sounds like a good revenue opportunity for the lawyers.

The deal made some good news copy. How it exactly shakes out comes down to many complicated details. Among the issues are:

1. What happens with overlapping product portfolios?
2. What happens to customers involved with prior strategic relationships, such as the deals that Ericsson has with Juniper and Ciena?
3. What will happen with R&D?
4. How will competing sales teams be managed?
5. Who's going to lose their jobs? (Yes, reporters, this is the next headline.)

Kelly Ahuja, Cisco's SVP of Service Provider Business, Products, and Solutions, and Ulf Ewaldsson, Ericsson's SVP and Group CTO, said both companies were "pressured" by customers to further integrate products and provide more "end-to-end" solutions. The discussions, which started a year ago, arose out of the growing sense that customers needed a more wide-ranging approach to building complicated IP and mobile networks.

There is no doubt that the approach makes sense. This will expand an awesome array of product, sales, and marketing teams — and combine Cisco and Ericsson's service provider integration approach. But even after Ahuja and Ewaldsson had described all the details, I still had the same basic question, which I asked on the call: Why not just merge?

"You gotta move fast," said Ahuja, implying that a merger would have possibly slowed both companies down. "Speed is very important."

Alujah also said that strategic partnerships might be a more common option in the coming years, rather than the standard merger route.

"Both companies have a lot of experience with build/buy/partner," said Ahuja. "The need is going to be all about strategic partnerships. I think there will be some more. This will be the new way of getting things done."

That's fine, but the trend over time is for industries to consolidate — and I predict that this is the first step in an inevitable merger. There are deeply engrained business drivers to merging: economy of scale, pricing power, and market power. By merging, the two companies would also save a boatload of money on marketing. Why carry two brands if your "virtual" operation means having just one? (Disclosure: It should be noted that consolidation in general does not help the analyst and industry media business.)

A merger would also likely have more shareholder benefits: Not only would the consolidation result in cost savings, but given Cisco's stash of overseas cash, there could also be substantial tax savings.

One big roadblock to any merger might be concern about regulatory oversight, and whether the U.S. government and the European Union would allow it to happen. A merged Cisco and Ericsson would be by far the largest networking and telecommunications purveyor on the planet.

But they didn't merge. It's a faux merger.

The spirit of the deal makes sense, but the customers will be watching very carefully. In the end, I do not think this marks the dawn of the new "strategic mega-partnership" era. The two-decade trend of consolidation in the service-provider and equipment market will continue, and this is Cisco and Ericsson's way of testing the waters — both with customers and with shareholders.

The urge to merge remains as strong as the law of gravity. You haven't heard the last of this one.