"How and whether specific mathematics might lead to improving the world (whatever that means) is usually impossible to tease out, but mathematics collectively is extremely important."

(https://mathoverflow.net/questions/43690/whats-a-mathematici...)

It can still be a good long term investment for society even if individual researchers are primarily motivated more by understanding than application. Arguably it’s the best approach we have because reliably predicting which ideas will be fruitful is super hard