Maybe we should've seen this coming. There's been a brain drain lately at Polycom (NASDAQ:PLCM) as networking companies have been picking top people off from the C-suite of the unified communications specialist.

Last week Brocade Communications announced it had hired away Polycom's chief information officer, while on the same day Riverbed Technology said it plucked its chief marketing officer. Of course, in July, Polycom's CEO resigned under a cloud after an internal audit found irregularities in his expense account.

Now an analyst at William Blair says its chief rival, Cisco (NASDAQ:CSCO), is ending its relationship with the audio- and video-conferencing equipment maker, a move that could cost it some $50 million in revenue annually and swipe $0.08 per share from its earnings.

The videoconferencing market has gotten more competitive even as it has undergone consolidation. Cisco bought Tandberg in 2010 for $3 billion, Logitech purchased LifeSize for $408 million, Microsoft spent $8.5 billion to acquire Skype, Polycom bought Hewlett-Packard's visual collaboration division, and Avaya bought Radvision, all with expectations that the expansion the industry was enjoying would continue.

But 2012 upset the apple cart, with broad declines across the board, though analysts thought it was an aberration and videoconferencing would rebound this year. That apparently hasn't worked out according to plan -- the first quarter of 2013 got off to a rocky start, with Cisco witnessing a 17% decline in revenue and Polycom suffering an 11% drop from the year ago period (and down 12% sequentially). It didn't get much better in the second quarter, either, as the equipment market dropped another 10.7% from 2012's level and 5.5% from the first quarter.

In retrospect, 2011 was a watershed year for the industry, and worldwide revenues have since plunged by 34%. So when we see the struggles Polycom is going through, it's no surprise management is jumping ship for calmer waters and Cisco wants to drive a stake through the heart of its biggest rival.

Cisco was already weaning itself away from Polycom, as it announced earlier this year it was moving to another vendor for IP conference phones, so this analyst note really might not be the big revelation it otherwise seems, and could explain why Polycom's stock has barely reacted.

As the unified communications specialist moves to more software-based platforms, such hardware-oriented news might be even less damaging. While the whole industry has been down and its executive suite has suffered a bit of turmoil, Polycom has largely held onto its market position.

At around 16 times expected earnings -- admittedly, earnings that don't take into account the William Blair analyst's expectations of an $0.08 per share hit -- Polycom is parked in between Cisco and Logitech at either extreme, but it doesn't seem to me it will remain at that level for much longer.

Fool contributor Rich Duprey owns shares of Cisco Systems. The Motley Fool recommends Cisco Systems, Logitech International, Polycom, and Riverbed Technology. The Motley Fool owns shares of Microsoft and Riverbed Technology. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.