This is an academic paper, not a government proposal. Veganism is not being advocated:-
As a result, processed meat consumption would decrease by about one serving per week (12 g/d) in high-income countries and less than a third of a serving per week (4 g/d) in upper middle-income countries. As consumers are projected to partially switch from processed meat to unprocessed meat and other substitutes such as poultry, red meat consumption would remain largely unchanged in those regions despite its increase price.
The authors also include the following caveat:-
Both our health estimates and our emissions estimates would change depending on the food groups that would compensate for the reductions in processed meat consumption. For example, greater consumption of sugar and refined carbohydrates, something that is associated with negative health impacts [51], could compensate some of the health benefits associated with lower consumption of processed meat.