Also, their market share is being eroded from the bottom, as nowadays Asterisk-based call-centers are ubiquitous. You just need an Asterisk ISO (or appliance) and some additional software for statistics and agent interactions - like https://www.queuemetrics-live.com/ - and you can run a 50-agent inbound/outbound system in minutes. So much of what used to be a captive market for big PBX makers is now gone. And the numbers we see are very significant.