Laziness is not a factor but rather the varying circumstances of...

Laziness is not a factor but rather the varying circumstances of the farming day make the farmer disorganised and there is always a long "to do list". As fast as jobs get ticked off more bob up. Tight finances mean that always farms are short staffed and sometimes the jobs left undone due to lack of time turn out to cause a problem.
Talking best practice is fine but you need plenty of skilled hands and enough money to achieve it. Farmers do not get paid enough for their milk and the price is controlled by the major buyers. Look at the debate going on now with "loss leader" milk at $1 per litre in the supermarkets which will eventually flow onto farm prices.
I always pay about $4 or more per litre for top quality milk. Tastes better, is better, and gives the farmer a better price. Many boutique dairies are now producing this type of milk and I have difficulty getting it because it sells well and is always sold out at the end of the day.