- Although the material or concept being studied does not make much sense now, we don't know what might happen in the future. While this isn't always the case (sometimes, physics and chemistry make it apparent (sometimes taking some work) that studying something for a given application will be fruitless), it is true that you often don't know. For example, liquid crystals (what is in LCD displays) were discovered in 1888. No major applications were even thought of until between 1950 and 1960 and they weren't commercialized until 1968 . Now, these displays are found almost everywhere. Similarly quantum physics was seemingly an academic extraction until it became important for understanding semiconductors and industries developed that needed it. Einstein's theory of relativity had no practical applications that could be commercialized until the space age, satellites, and wireless communication made it necessary. Few would argue now that these were unimportant or fruitless studies.
- Sometimes concepts are learned about one system that can be applied to other, more useful systems in the future that may or may not yet have been discovered. Also, sometimes these "model" systems are investigated because they are less expensive or easier to make. Sometimes it is easier to learn something about one system and apply it to another than to make samples and study the other system, straight off. You don't always know which technologies will succeed and which ones will fall by the wayside.