This question comes down to the context of the investment. At first glance, this may appear to be an absurd question. A BMW is an automobile and as such is a depreciating asset. BMWs are high end cars and thus, will cost you a lot of money to purchase new. Therefore, after spending a lot of money, the BMWs value will continue to decrease. Additionally, the BMW has reoccurring costs such as maintenance, oil changes, and gasoline. Therefore, a BMW will cost you more money that will not be returned monetarily. However, a BMW is a mode of transportation that can make your life easier and can get you to important places such as work. Therefore, in exchange for a large initial cost, relatively small recurring costs, and a complete loss of monetary value over time, you will have a means of convenience and a way to travel.
A bachelors degree, on the other hand, does not have recurring costs. However, like a BMW, a bachelors degree can be very expensive depending from which university that you obtain your degree. However, unlike a BMW, a Bachelors degree can cause you to get a better job and a better career. This can lead to more money and a better reputation in your career field of choice.
If the analysis stopped here, the choice would be obvious. However, given a different context, the BMW would be a better choice. For example, if you are a car collector and you bought an extremely rare BMW, this car would be a far better investment than a bachelors degree. Additionally, if you obtain a bachelors degree in a subject that is based primarily upon your own personal fulfillment rather than on employment advancement, the BMW may be a better choice.
Another situation to consider is if you never use your bachelors degree. If this is the case, then a BMW may be a better investment because even though you do not get any monetary return from your investment, you do get convenience. On the other hand, even if you do not use your bachelors degree, you do get educational value from it. Therefore, the question becomes which asset to you value more, convenience or education?
Ultimately, the entire analysis depends on the context. In the most common situation, the bachelors degree will always be a better investment than a BMW. However, as certain circumstances come into play, the BMW may be a better investment than the bachelors degree. As such, depending on the purpose and situation for the decision between a BMW and a bachelors degree, either one could conceivably be a better investment than the other.