I blame Seinfeld for popularizing the "Marine Biologist" profession to include many individuals without the necessary passion for the job.
All kidding aside, when I went through the UW School of Fisheries Science undergraduate program in the mid 90s, I expected everyone to be as passionate about fishery resources as me. I hoped to meet a lot of like-minded people who I could later fish with. Turns out most showed little interest in angling and were content if the subject was whales, turtles, butterflies, razor clams, or whatever. Nothing wrong with that but I went there specifically to learn about salmonids because that was what I fished for and wanted to make that my profession. I was shocked how many students didn't even fish recreationally. There was one who after finishing, moved to Montana and became a full time trout guide. Some of the rest, while passionate about animals or their environment, seemed less interested in actually managing fisheries. And still more became dissatisfied with seasonal, temporary, low-paying jobs and felt it would take too long to climb the ladder and left the field entirely. Since then, I have learned that If you wanted to climb the ladder and get into actually managing fisheries, you needed a lot of perseverance, an advanced degree, with a strong science, statistical, economic, political, and cultural background, to go along with a resource management background. I'd like to think that those who fall into those positions are well qualified, with a strong, diversified background and are weeded out from the "wanna be's" in the process. I think that will still hold true in the future, even if the OP's opinion is skeptical now while evaluating his/her classmates.
Approaching 25 years in fisheries (the last 22 with the same employer) and a stop along the way for a graduate degree in natural resource management, I couldn't see myself doing anything different. Rubbing shoulders with many in the field, most at least pursue outdoor activities and I've found more often than not, many in the fisheries field have wildlife backgrounds and often prefer hunting than fishing, which is fine. There were more jobs in fisheries than wildlife, with all the ESA listings and such so that is where they ended up.
Twenty years ago my supervisor asked me where I wanted to be at the end of my career. At that time, I told him I wanted to manage a world-class (recreational) fishery. The four examples I used was Yellowstone Park cutthroat trout, Kamloops rainbow trout, Skeena River steelhead, or Bristol Bay sockeye. I still think those would be great jobs to be involved with. Anymore, I think it would be interesting and challenging managing the social aspect of recreational fishing and matching that with conservation constraints to administer a well-managed recreational fishery. Maybe not here in WA (unless it were a stillwater trout program) but somewhere else where natural populations are still relatively healthy.
To the OP, I wish you luck and to not lose faith.