First, Avaya does run on common x86 servers as well as virtualized and has for many years. Linux and Xen if fact. Many implementations of freeswitch/asterisk fell apart as they simply don't scale to thousands of users. Yes, I know about Kamailio. Scale doesn't just mean have 50,000 endpoints register to the system and handle the busy hour call volume. It needs to be secure (Avaya encrypts H.323 and SIP very easily (Cisco actually doesn't do well here)). Which means you need to be able manage certs for each gateway, phone and application server. It's needs to be manageable with have full access control and it needs to provide the tools support the environment. A rich ecosystem of proven integrations help here too. Further, contact centre, when you have 1000 agents, or 25000, the cost of each of those agents doing nothing on a revenue contact centre because of a system crash is wildly expensive. Further, in the event of a major failure of a DC, many such customers also require triple redundancy with each system being able to failover with limited or no impact to the business. Federal governments require certifications that are very arduous and require substantial techical resources and capital. I could go on, but this mostly covers Enterprise and federal government. Now for small businesses it's a completely different issue. FreePBX is ridiculously difficult to configure. Very few people have the skills to understand how to develop and build a dial plan, how to integrate with SIP Trunks from a carrier, and even if they manage that the gateways that are from these other companies have a completely different interface and a completely different skillset. It's simply too hard especially when I can go and pay a small amount per month and either get some kind of a cloud service. Probably the best example for a commercial/open source offer is Digium. But they haven't gained substantial market share compared to the likes of Avaya IP office, Shoretel, Cisco, etc. However, if you do the math, these small systems are actually cheaper than cloud provider because you can run them with very low recurring expense. In my opinion, Avaya doesn't have a long road ahead. But it had nothing to do with their technology, nothing to do with their business practices, it was entirely the destruction of a business by a private equity firm who thought they could make a quick buck but completely screwed up.