Note that one of the largest and reliable systems -- smart phone to internet gateways often run Erlang, another functional and language with dynamic (but strong) typing.

So when you watch cat videos on your smart phone, there is about 50% some non-statically compiled functional code has done its job in setting up the necessary signaling.

WhatsApp has also recently been the poster child for running a successful distributed platform, with a tiny number of engineers (about 10 or 20) by also leveraging a non-statically compiled and functional language.

In general static type checking is nice, I like it. But clearly not a deal breaker. O often hear "I won't touch anything unless it has static typing" or "large applications should have static types".

But maybe the question to ask, should applications be that large? Lately we have been all upvoting microservices. And if anything those encourage decoupling large monstrous application into smaller independent services. At that point there are just a soup of dynamically typed components.