Assembler isn't lost? It's still very common in hardware development.
There was an option in the old CAPEX optimizing COBOL compilers I used back in the 80s: you could print out the IBM 370 assembly language it generated from your COBOL source -- a look "under the hood", so to speak.
The same thing was thought of assembler programming a few decades ago. Now it is rather a lost art. I fear that a day would come when machine learning algorithms can write code on their own and coding itself would become a lost art like assembler has become now.