Asterisk has a huge developer base that these companies cannot compete with. As a result the number of features being developed and integrated into Asterisk is phenomenal and these comapnies can't keep up. Similarly, creating new services in the Asterisk environment is easy because of its open source nature - comapre this with the conventional proprietary systems we are all used to. The main reason however is the design which enables developers to create new services using the Asterisk Gateway Interface (AGI) or the C API.

I am sure there are many companies already doing this, and if not, will be doing it soon if they have any sense. However, I don't expect these companies to advertise the use of Asterisk in their systems, which is possible via the purchase of a commercial Asterisk license from Digium.

well done Asterisk

Editor Note: I found this blurb while reading about Asterisk. A nice comment might I add.

Source: Jay Bee Pee