According to a study reported by Channelomics, "A new report by the Kauffman Foundation, a non-profit economic think tank, finds the number of U.S. technology companies five years or younger has fallen precipitously compared to the peak level in 2001."
One reason cited is consolidation. No kidding. Those "synergies" that Comcast talks about in its acquisition of TWC means layoffs. Why can't they just say so?
The other reasons include retirement and people leaving the channel.
Microsoft partners who made their living from hosting Small Business Server and Exchange have seen those lines of service close or shrink. Most Microsoft partners don't want to be salespeople for Microsoft services making a quarter per inbox. They are techies who only sold when they had to. Hardware VARs and PBX inter-connects have been feeling the effects of the shift to cloud (as have their vendors who have also been shifting to managed services - competing with their channel partners.)
All of this results in less people working in telecom, which shouldn't be a surprise. I know quite a few people who gave up on telecom in the last four years.