It could also be that they don’t know how to optimize PHP settings. OPcache is amazing for performance, but by default caches only 1/5th the number of files in an app. I boost that to 20-40k just to ensure performance.
Edit:
Ouch, I just looked at the Dockerfile. No wonder it is slow! He misconfigured the Laravel tests. The built-in PHP server is known to have less than optimal performance, and he used NGINX as a reverse-forward proxy to it. Not cool. At least set it up with PHP-FPM + nginx to see how it really runs.
EDIT: I did open an issue.
I would refer you to TechEmpower's benchmarks anyway: https://www.techempower.com/benchmarks/
Laravel is known to be slower than other frameworks. But it's still in the 50-200ms response time. I just deployed an app to an AWS medium node, and basic pages respond in 31ms. DB intensive pages run in 55ms.
^ this is a production app/environment.