Head start is the wrong wording, I've amended the post. I should clarify that he was given room for error under context of joining half way and needing to stabilise the team, learning on the job and making his own mistakes - but was broadly still quite poor.
Ultimately he took over a club with better resources and a better squad than to finish 8th back to back, and was capable by year 3 to make top 4. He actually underperformed these benchmarks back to back for 3 years until he got things going in season 4. The "but he's learning on the job" argument doesn't quite cut it there.
I think what is moronic is throwing money spent around when we both know Ten Hag works for clowns that overpay almost every transfer by 30-40%. Moreover, you want to consider Arteta's lack of support and ignore that when Ten Hag joined we had global scouts sacked, no real structure in place to challenge his own suggestions and an academy player's brother brought in as an emergency to negotiate contracts for new signings. This affects transfer windows too. It's a bit weird for you to talk about Ten Hag's backing in absolute sums, and not actually dive into anything about the structure.
You actually haven't debunked anything - you keep hiding behind this "Arteta is allowed because he's learning on the job" without actually considering that the expectation on him was to do better than 8th twice and 5th for his first 3 seasons, even when considering him learning on the job.
You've tried to pretend that Arteta has shown clear progression since he joined year on year which is such frankly, nonsense. How one can say a manager finishing 8th back to back with 4-5 points between the two seasons is "progression" is beyond me. As I said, if Ten Hag finished 8th in season 1 and 6th this year, he'd get sacked quite quickly, despite showing "improvement" by your own logic.