Having designed similar systems, I agree completely. This is not a language or framework problem, but system architecture.
I have used RabbitMQ to great success as the message queuing system, and there are many other good alternatives.
In a system that requires a response to the customer within a few milliseconds through web api, how do you ensure the performance in Python? I'm genuinely interested as that sounds outside of what stock CPython can do except trivial logic.
Another aspect that's completely ignored are the requirement - you might need the response time in milliseconds, couple of times per day. Others might need to serve hundreds of requests. You also need to consider the budget available.