The point of an economy is not to spend money, it's to create more wealth for more people by allocating resources efficiently. If someone "hoards" money, and prices are stable, that person is effectively staying out of the resource-allocation business. It doesn't mean that there are fewer resources to allocate, it just means that other people are doing the allocating (even though those people collectively have less money because of "hoarders", prices are lower because of them, too).
You can make an argument that everyone needs to take part in efficiently allocating resources, and that makes a lot of sense. But to say that buying a bunch of consumer junk is a good way to do that is ridiculous (and bad for the environment).
A middle ground is to buy the things you need, a few things you want, and make conservative investments. That allows most individuals to mostly stay out of the resource allocation business, but still enjoy the benefits.
If you are on top, you wouldn't want to make extra effort to stay there!