There is a lot of misinformation in this thread, probably based on the perception of posters own situations vs the reality.
Travel continues around much of Europe, with few restrictions. I can vouch for that. And there are Americans travelling in Europe, as several countries do allow them entry. I can vouch for that as well. (And there are many, many more Canadians than usual or they stand out more right now, as Canada is welcomed to much of Europe)
For any American looking to travel to Europe, there is a thread on Flyertalk.com Coronavirus and Travel forum which outlines the various countries and how people are gaining entry and able to travel. The RKI site also has a daily update of restrictions or risk areas for Germany.
https://www.rki.de/DE/Content/InfAZ...ebiete_07102020_en.pdf?__blob=publicationFile
The reality is that borders cannot stay closed forever. Germany has opened to Canada for a long time, but also did not lift the travel warning to Canada (they did lift it for much of rest of world) because Canada still requires 14 day quarantine, and will not allow entry to Germans under most conditions.
And while flights are of course very reduced. every single one that I have flown in the last six weeks has been fully booked. Lufthansa is managing loads well and adding more routes and destinations daily.