This is partial truth. In my city the cows roam on roads and all the shop keepers feed them before they start businesses. Do you think , if there is no dairy consumption...cows will be in to extinction. As I am said in above comment, the torturing of cows done in industries and where they kept in huge number for dairy.
The farmers are best and they take care cows passionately. The thing you have said for leather is mostly from north India, in South we don't encourage this. As much as for hindutva, cows are considered as mother because the children after mother's milk raised by cows/buffalo's milk. That's an association between the cows and people.
Also it's depend on individual, can't generalized.
Do you know what happened to horses in Britain after introduction of motor vehicles? All the horses are abandoned on roads and most of them starve till death.
Religion aside, the this a business and I advocate for fair,compassion and good treatment for the cows rather than seeming as products/milk machines.