What? We've (JavaScript and developers dealing with asynchronous patterns) been able to build scalable (in terms of code and its maintenance) for many many years, probably 10+.
async/wait is simply syntactic sugar and doesn't drastically change anything, you still need to understand the asynchronicity underneath it all, and if you do, you won't have any problems building scalable apps using your knowledge.
It's a complete shift in application design...
If I have to flatmap one more time...
Absolutely, asynchronous and synchronous are two very different patterns when programming with very different trade offs for both of them, but async/await is not synchronous, it only make that particular call _look_ synchronous, while actually being asynchronous.
Failing to understand that async/await is just syntactic sugar for dealing with asynchronous programming will sooner or later bite you.
Here is a gist that shows why async/await is not really synchronous (blocking) programming: https://gist.github.com/matt-mcalister/3f060bf32d292cfebc944...