To be clear, we are not talking about a boom and there are still plenty of risks out there. But globally things are better. Animal spirits have been missing for quite a while and they might just be starting to come back. 2. At some point, the cyclical upswing will run its course. Beyond that, much depends upon demographics and technology.
Here there are reasons for pessimism and for optimism. Many developed economies, as well as China and Korea, face big demographic challenges. Populations are stagnant or declining. They are also ageing. Older societies want to save, rather than invest, especially so when there will be fewer people tomorrow than there are today. And older societies are likely to be more risk averse.