The architectural switch to the "Flexible Environment" is what I missed. I can appreciate why this broader new approach for language runtimes took some time.

But then again the Flexible Environment seems to be a very different product with different features/characteristics and pricing than what I once knew as "App Engine". I would then argue that Python 3 never came to "App Engine", only to their new product. Which is a valid strategy for Google of course, but now stifled my enthusiasm. Probably I only need to learn more about Flexible Environment style App Engine to become hyped again.