Of course it would be better for the planet and our wallets to not eat meat, but our diet more or less requires some amount of meat for iron and protein

I think people really get a skewed view of this. It's better for our planets if we eat less meat, and if people who need high protein intake won't stop eating meat it's a bit better if you eat zero meat to competensate. But it's a "little vs a lot" thing . We still need meat to support the horticultural industry.

I mean, the cows and pigs in my area serve the important purpose of providing much of the fertilizer for all the vegetable farms in my area. They would still be there, getting fed, if nobody ate them or drank their milk. Their deaths would just be more of a waste. There is a point where too many cows/pigs are producing more fertilizer than crop farms need. But you want to hear something scary? WE AREN'T THERE YET; not even close. In the US at least, we only produce enough manure to support 20% of our horticulture, and the rest is supplemented by compost and synthetic fertilizer. And that synethetic fertilizer? Pretty terrible for the ecosystem and wild animals as well.

The real answer is that we haven't solved the problems. It does "feelgood" to know that we can genuinely help a little by eating a little less meat. And we should all be doing that. But all of us going vegan is a real problem for reasons unrelated to the (very real) nutritional issues.