Facebook's sliding stock price has at least one hedge fund manager predicting a dismal decade ahead for the social network.

"In five to eight years they are going to disappear in the way that Yahoo has disappeared," Ironfire Capital founder Eric Jackson told the CNBC show Squawk on the Street on Monday.

"Yahoo is still making money, it's still profitable, still has 13,000 employees working for it, but it's 10% of the value that it was at the height of 2000," Jackson added. "For all intents and purposes, it's disappeared."

So how exactly does Jackson see Facebook's power eroding by decade's end? He says it will be the continued emergence of the mobile web — and Facebook's struggle to adapt to that paradigm shift.

"The world is moving faster, it's getting more competitive, not less," he said. "I think those who are dominant in their prior generation are really going to have a hard time moving into this newer generation.

"Facebook can buy a bunch of mobile companies, but they are still a big, fat website and that's different from a mobile app."

Facebook bought the wildly popular mobile photo-sharing app Instagram — which some saw as a potential rival — for $1 billion in April. Still, the company has acknowledged mobile as a potential stumbling block for sustained growth.

In its required initial pre-IPO disclosure of 35 "risk factors" released in February, the company admitted that as mobile use of Facebook and the web in general continues to expand, its ad-free mobile platform will become more problematic. In an amended filing in May, the company underscored that challenge again.

Facebook stock officially went on sale on May 18 at $38 per share. It closed Monday at $26.90.

Jackson sees Facebook as a member of the second of three generations of modern Internet companies. The first generation, highlighted by businesses such as Google and Yahoo, served as portals that organized and aggregated the web's wealth of information. The second generation, most notably Facebook, capitalized on an emerging social web.

The third generation is made up of companies whose sole goal is leveraging and monetizing mobile users.

"When you look over these three generations, no matter how successful you are in one generation, you don't seem to be able to translate that into success in the second generation, no matter how much money you have in the bank, no matter how many smart PhDs you have working for you," Jackson says.

"Look at how Google has struggled moving into social, and I think Facebook is going to have the same kind of challenges moving into mobile."

What do you think Facebook's status will be in five years? Share your predictions in the comments.