The patty/bacon should definitely not be cold and that's not my experience with McDonalds. However it is less warm than "scolding hot from sitting under a warmer for 45 minutes."
McDonalds was an assembly line for burgers. As far back as the 80s, and as late as last year, in Canada, during busy times, they'd definielty have burgers under the warmer. During slow times, none.
They can cook and assemble a burger in 2 minutes, along with fries... even a dozen burgers.
This was McDonald's specialty! How to keep ahead of the crowd, in sync with demand, and also, how to build a burger fast.
The fact that they don't have 50 big macs on the go, during doordash/dinner peak, is a major problem.
No, it's not difficult, not for them, they've been doing it for 70 years!
There may be some merit to some of what you say, but it just leaves one with more questions.
