Why does it feel as though only the US and China (and maybe some other Asian countries) have an economic future?

Countries go through rises and falls. From an American perspective, I still think of Germany as one of the best European economies. German products are still considered top quality and Germany itself seems a place people would like to be for a number of reasons. Maybe you are too familiar with Germany's current issues to see it fairly compared to other countries.

You probably know more European history than I do, but look at England's global dominance a century ago compared to now, or further back at countries like Belgium or the Netherlands. It's all a dice game at any time which country is in the right position at the right time.

The US is still riding the wave of economic benefit of being the major player that didn't have its infrastructure ravaged by 2 world wars. We were able to sell everything to everyone after that, and it left us in a great position to be able to take advantage of the computer age.

It will probably be an energy (nuclear/fusion/battery) or space technology breakthrough that will bring the next huge economic breakthrough for whomever comes up with the answer to those problems. I don't see anything putting Germany in a bad position for that kind of thing. The catch that I'll say exists now that didn't before is our ability to travel and communicate so much more efficiently than ever is there are far fewer sole American, sole German, etc companies that the money from a boom will probably be spread around more than in the past, so economic waves may be smaller, yet more frequent than huge booms and busts in the past.

As far as China goes, the impression I'm able to form is they are able to do what they do by doing what many countries would consider to be cooking their books. They seem to have much greater control over their economy and businesses themselves and their currency to push their agenda, to good and not so good ends. I don't invest in China due to what I see as a lack of real transparency.

At the end of the day, it all comes down to luck though. Things like climate change, immigration, and wars are always going to interfere with the plans of the greatest leaders, accidental discoveries will be made, and multitudes of other factors will pick our future winners and losers. It's much easier to look back and say, it's obvious we should have done X back then than it is to look forward and correctly say we need to do Y now.

Germany will survive, as it will have to change with the times sooner or later. You'll form trade and political alliances with different players as your economy changes. Young people will learn different careers as we did to join the age of technology and how our grandparents handled mechanized agriculture, airplanes, and automobiles. This area in time will likely be a blip in history, it's just more important feeling because it's our here and now. I don't think you'd feel Germany is not at least in the top half of European nations, so that still puts you ahead of the majority. We're all struggling now, but we'll still wake up tomorrow and figure things out.

I hope that gives you a more comfortable take on things from an outsider with a passing interest in world economics.