The problem with Django services is the insanely low concurrency level compared to other server frameworks (including node).

Django is single request at a time with no async. The standard fix is gunicorn worker processes, but then you require entire server memory * N memory instead of lightweight thread/request struct * N memory for N requests.

I shudder to think that whenever Django server is doing an HTTP request to a different service or running a DB query, it's just doing nothing while other requests are waiting in the gunicorn queue.

The difference is if you have an endpoint with 2s+ queries taking 2s for one customer, with Django, it might cause the entire service to stall for everybody, whereas with a decent async server framework other fast endpoints can make progress while the 2s ones are slow.