This just unequivocally not true. Everyone is treating his/her question as if it has a distinct right or wrong answer. The best advice I can give is this; do some investigation of possible universities and their Japanese language classes. As with most things in life, some are going to be better quality than others, but if you are able to choose a University with a quality language course, then I would argue it could be beneficial.
For example, Middlebury College in VT, USA is one of the best language Universities in the USA.
Many people here are framing the answer/question as “what I’m going to get out of the class, what is the class going to offer me, etc” I think it’s important to understand that, again like most things in life, you get out what you put in. While I recognize the fact that some teaching styles/course may not be conducive to learning at maximum efficiency, it still comes down to how someone utilizes the resources they are presented. Taking Japanese language classes has benefited me tremendously; it introduced me to people who share the same interests and goals as myself (important when trying to study, or practice, etc), I was able to practice listening, writing, and speaking, and the regimented classroom style helped me organize my learning. There’s nothing to stop you from going ahead, or doing self study. In fact, that’s encouraged, but I can’t see how getting more “reps” in could ever be considered a bad thing.
The fact of the matter is, most people do not have the self-discipline to maintain a consistent self-study routine. They often burnout, or slowly stop following the routine. I’m not saying that @_josh is going to burnout or lose motivation, but for most people having a regimented-classroom-style environment helps keep them on track. He/she said that they will study for 25 hours a week, which means that in order to study 2200 hours (roughly the amount of hours to become ‘fluent’) they will have to study consistently everyday for almost two years. Not many people can do that.
As for the price, if you are looking at only taking a few classes at a time, the price isn’t necessarily always going to be that expensive. There are plenty of opportunities for scholarships, grants, financial aid, etc.
For me, since my primary degrees are in electrical engineering and computer engineering, I already had scholarships so the Japanese classes were added at not additional cost.
As for this rhetoric that American universities somehow lack quality, or will not provide a good education, I have nothing to say to that other than, it’s false.