No. I think Nintendo are the cause of their own demise. Still, the thread title is incorrect - Forbes =/= Forbes Contributor.

I don't see how the iPhone 6 could have any greater impact to the video game industry than any previous iPhone or smartphone. It's just another update to a phone. Sure, they sell way more than video game consoles and handhelds, but they're selling the same rate (if not more for some) than consoles that came out when smartphones weren't around. DS came out right at the advent of smartphones, and is the 2nd greatest selling console of all time. 3DS, while not quite as successful, is still generally the 2nd highest selling console each week. The video game industry really has no reason to worry.

Nintendo's yearly handheld shipments have declined every year since smartphone apps really started to take off (2009) now to their lowest point since 1997, that's before even the Game Boy Color came out. Nintendo is forecasting this year to be lower than even last year. 

Vita can't even sell at Sega Saturn levels.

Neither the 3DS or Vita can manage to maintain PSP level sales (forget DS or even GBA) currently. 

Waiting in any airport when I travel (which is quite often for work) I'll see kids playing on their parents phone/tablet for every kid I see with a 3DS, I see 10 playing with their parents (or their own) smartphone/tablet. Things have changed. Big time. 

I'd say we're well past the "worry" phase at this point. We're into the "accepting the market has changed forever" phase now.