I stumbled upon an old Github repository of mine yesterday. A machine learning research project written in C that classifies time series. As I was going through the dusty code, I was reminded of my beginnings as a programmer, learning C in middle school.
The development time is much lower, because you don't have to do low-level things like defining variable types or allocating memory usage. And since developers are more expensive than less efficient code, we prefer sacrificing performance for readability, speed, and maintenance. It's understandable: software development is already hard as it is, so why bother introducing more bugs and more complexity?
But if we look at it in terms of performance, strongly-typed programming languages have a few non-negligible advantages. Compared to C, Python is a huge gas plant. When you look at it in terms of accessibility, energy consumption, and cost savings, low-level languages are much more resilient.
For now, the technology isn't ready to disrupt the last decades of web development, but there are hybrid solutions. Technologies like Google's Accelerated Mobile Pages, Svelte 3, or this list of opensource Wasm projects, are good examples. Exciting times to be a developer!