Not being argumentative, but I don't think you can make the assumption that the system is inherently wasteful.
A lot of the research on it is extremely generalised, mainly focusing on the worst cases from the myriad of systems in the world from coos in fields, to coos in feedlots (the majority in the US, AFAIK).
Most of the grazed land here (82%, in fact), particularly for sheep, is unsuitable for growing veggies/crops on, as it's too hilly to be combineable and too exposed. That's why we've got specific wooly breeds of coos and sheep (and you thought that was just for the tourists).
A lot of the 'takes 1,000 litres of water to make 1kg of beef' arguments don't apply here as much of that is rain falling on the land anyway and it's not 'lost' per say and if some cases harnessed.
There is water usage in the processing, but that's to ensure everything is kept clean and no-one is poisoned, so I'm not sure it's 'wasteage' as such, and with water metering they are all having water usage to make sure not one drop is wasted (again, for purely financial reasons).
By our calcs, 1kg of beef produced by an upland suckler system requires an intake of 0.9kg of people suitable protein (a lot of the time it's actually whiskey leftovers, smells DIVINE) + plus a big load of grass.
We're working on the burping, mainly looking at natural feed supplements that would make them a bit less burpy and help make feed conversion to meat more efficient. GHG emissions are down 12% from 1990 at the moment.
Sorry, still on the meaty payroll, so I'm compelled to robustly defend. :)