Money is not a commodity or a resource; it’s a symbol. It’s a symbol for the value attached to things. Capitalism teaches that this value, though it may change by the day, is Good & True. Libraries, for instance, are worth next to nothing nowadays. (I’m speaking about the Netherlands.)
If you or I or the Collective Spender have too little to spend, that’s simply a reflection of our value. There can be no lack of money in the global society as a whole, since it merely reflects its values.
If this society yet seems to be getting poorer, there must be a leak somewhere, a slipping away of value.
That’s easy to spot. Megatons of stuff are produced every day only to be converted into megatons of waste the next day. And to get rid of it properly costs us extra. (So we do it mostly improperly.)
The solution, therefore, would seem to be to produce less stuff that lasts longer: by being more durable, and by giving us deeper pleasures. Objection: fewer people would earn a living producing rubbish. On the other hand, we would have more money to spend on creative work, education, healthcare and libraries.