It would be as if Facebook decided to focus obsessively on serving college students. It's a good initial strategy, but eventually you have to serve bigger markets.
If I were in charge at LinkedIn I'd focus it on becoming the number one place for professionals to exchange information, create and manage events, and connect with like minded colleagues.
There's a huge potential in this because most professions don't have particularly good online social networks. Oftentimes they're old fashioned discussion boards behind paywalls, comments sections of popular blogs and other half-ass solutions.
Interestingly, my vision really wouldn't do much for software engineers and developers. I think StackOverflow, meetups, and other resources already provide this.
It boggles my mind that they didn't take this route and instead they became the social network for the unemployed as another commenter aptly described them.
It's a business school case study waiting to be written.