You can see from the graphs above that when dealing with only CO2 there is a marginal increase in how much worse chicken or fish are compared to alternatives which aren't as nutrient rich.
A 3x increase isn't nearly as high as people would like you to believe. Let alone milk which is more eco friendly than many of your common calcium alternatives.
Not only that but dairy plans to be carbon neutral in the USA as of 2050.
You can paint eco-friendly husbandry practices terribly as much as you want, but real progress is constantly being made. These same industries are the ones actually investing in lab grown meat.