However, these individual actions might collectively have unintended consequences, and that's what the paradox of thrift is about. It's a descriptive concept (i.e. about what happens in the real world), not a normative one (i.e. what people ought to do).

But before you decide what one ought to do, it is best to take into account what actually happens in the world.

It might well be better if people spent more (and that need not be on material things, it could be education, concerts, and so forth).