Are internships necessary?
Depends on your field. I know MSFT makes full time offers to about 80% of its interns. In CS internships do help quite a bit because when you go to hire someone to be a programmer, you want them to have some experience writing programs. If all they have is experience doing programs for CS class work, that doesn’t really cut it. Alternatively, if they’ve done a bunch of programming on their own, either for fun or profit, but not inside a formal internship, that’s just as good and I would hire that person as well (if not sooner).
I think the point is that experience is important for finding a job, even an entry-level first-real-job-out-of-college job. If you already have the experience you need for the field your in then I wouldn’t worry too much. For those who don’t have much experience in the field they want to enter, internships are one the primary avenues for acquiring some. While the paycheck may be small (or even non-existent) the payoff down the line can be huge. I certainly wouldn’t overlook them.