The company (Nethesis) needs to have a business model so that it can sell software, support and services to other companies, customers and resellers and part of that the revenue is used to fund development of NethServer, official site hosting, community initiatives, sponsoring and so on.
The community wants to be sure that all the contributions and all the hard work stays Free Software. That is guaranteed by the GPLv3 license.
Community and Company have the same aim: making NethServer better and more successful and NethServer benefits enormously from the resources that the company invests into it, including coding, marketing and more.
The company pays NethServer coders to write features the customers need and works with the community to make NethServer a better product. Because the company works in the open and as part of the community, and because the code is released under the GPLv3, NethServer itself continues to be free.
That’s a virtuous circle!
Essentially, Nethesis customers/resellers pay for developers writing more GPL code for NethServer. So we think that we found a solution here which is good for all parties and everybody wins!
As @davidep said NethServer is just ONE, because NethServer Enterprise is just a rebranded version with additional commercial modules.
We have been and still are very OPEN to discussion! It’s our core feature! 
We explicitly do everything in public on NethServer– it’s very intentionally the opposite of an Ivory Tower Development 
Obviously we want stay on our mission which is building the best distribution for server designed primarily for small offices and medium-size enterprise