Yes, I guess if what happens is the butcher closes and everyone locally eats less beef/lamb, then it is better for the planet. But I suspect what'll happen is instead of walking to the butcher, they'll drive to the supermarket for their meat. Or order online and have a bike/van deliver it. Which is not better for the planet at all.

I eat a lot of tinned pilchards. Must investigate their environmentally friendliness...