I quite like the magenta diagram, a picture speaks 1000 words as they say.
The issue for me is the combination of specially modified radio transmission rules, the limitations of see-and-avoid, different aircraft speeds, the intensity of arriving traffic, and people getting it wrong, such as descending out of cloud, flying the hold the wrong way, didn't quite know where the hold was so flew it at an offset (this magenta line helps
), and when to use the hold and when to leave it, and people cutting others up.
Having had these slightly uncomfortable encounters about 5-6 years ago, I decided I won't be flying into any busy event, particularly one that involves a hold, unless there exists good ATC to properly manage the stack / arrival sequence.
If we don't take part in protecting GA access to infrastructure, the smaller aerodromes will be built over, the larger aerodromes will have exorbitant handling fees and awkward procedures, and airspace will be over-classified to Class A everywhere.