Because it's a lot cheaper.
I expect that in my lifetime (I'm 40) the idea of eating meat from a living animal will come to be seen as repugnant and backward Third World practice. That won't comfort those of us who like real meat, but I can see it coming.
No.
Fifty years from now, meat that actually came from real animals will be like organic fruit and vegetables.
Robert Heinlein saw it coming in the 1950's.
From Coventry:
"It did not occur to him that these timid little animals, streaking for cover at his coming, could replentish his larder -- he was simply amused and warmed by their presence.
"When he did happen to consider that they might be used as food, the thought was at first repugnant to him -- the custom of killing for 'sport' had ceased to become customary long before his time; and inasmuch as the development of cheap synthetic proteins in the latter half of the preceding century had spelled the economic ruin of the business of breeding animals for slaughter, it is doubtful if he had ever tasted animal tissue in his life."