As the NFV reference architecture is largely defined by the telecoms themselves, they enforce the developments they need. It is radically different from the old paradigm, when the leading vendors were the major source of innovations and enforced standards, which secured their market leadership.
The opening of the telecom ecosystems allowed smaller vendors compete in niches, which were previously closed by the end-to-end solutions from the market giants. In the recent past, almost the only way for a startup was to be acquired by a giant soon after the creation. With the appearance of NFV, startups have much better chances to stay competitive in some niche of the ecosystem, grow and challenge the status quo.
Virtualization, cloud, disintegration - the foundation of NFV - allow developing and introducing new solutions and services significantly faster than it was in a world of huge "black boxes". If you want to test new software, you just deploy it in virtual machines, scale as the workload changes, turn off and delete the virtual machines if the related business model fails. By its software defined nature NFV enables and supports agile developments, DevOps and alike, which wipe off the gaps between telecom providers and the main competitors - other the top (OTT) providers like Skype, Netflix and alike.
The combination of the above gives the providers much more ways to innovate in business models and technology.