> Does it though? I mean I'm still teaching thread-safety and recursion to my interns... a solid foundation is a solid foundation.

I think you are confusing interiorizing some fundamentals with things moving fast. There are languages and frameworks rolling out higher level support for features covering concurrency and parallelism. While you focus on thread-safety, a framework you already use can and often does roll out features that outright eliminate those concerns with idiomatic approaches that are far easier to maintain. Wouldn't you classify that as moving fast?