"An HTTP Flood Python script that could stop a normal website in 10s" OR is it?

[EricBallard]

Hello all: I am researching network security and attempting to replicate a denial of service attack.

I see this project has quite a few stars. So as a proof of concept test, I was disappointed to see that after sending 10k request with this script, to my vps hosting a 'simple' python web server.
https://github.com/EricBallard/DDOSim/blob/master/src/servers/web_server.py

After what seemed like much longer than 10s, and 10k GET request later, the website suffered no dysfunction at all.
I'm able to confirm the web server did seemingly receive every request.

(VPS SPECS: 2gb RAM 2 vCPU, Ubuntu 18.04)

However while sending attack and consistently refreshing the page on my phone and desktop: The website was served responsively every single time.

So what am I doing wrong here? Is the web site/server too lightweight to replicate any real website, or does once machine not cut and the attack needs to be distributed?

Thanks!