> Don't place the economic value of your company to be ancillary to your product.
In other words: Don't do open core?
Dual licensing, more than any other common open source business model besides paid development, maintains the link between value of software produced and value for which customers pay. If a customer can't use the software under its public license, perhaps because the license requires release of code they want to keep closed, they pay for a license. The value of the software they become able to use, under paid license, sets the price you pay. Meanwhile, all the development work the vendor's people do goes into the product for which customers pay a price.
The article seems to imply that dual licensing is all or the crux of Mongo's business model, when it's only a relatively small part of their package offering. That can be hard to see, since both under AGPL and under the new SSPL, Mongo's choice of public license doesn't prevent developers from creating closed, proprietary applications using Mongo as data store. As they seem to intend it, Mongo dual licensing covers only platform developers who offer Mongo itself as-a-service to application developers. I hear tell the company has actually spent substantial time sending letters to users clarifying that they didn't need to buy a separate license to use Mongo in their closed apps under AGPL.