Made me wonder: how likely would it be that a modern ginkgo could not reproduce with an ancient one?

Someone should invent a game, that while playing demonstrates how much monopolies suck for everyone involved (except the monopolist)

Not really, many many more people are B12 insufficient than there are vegans/vegetarians. And much of what B12 you get is because supplements are given...to the animals. See e.g. https://baltimorepostexaminer.com/carnivores-need-vitamin-b12-supplements/2013/10/30

You do have direct control over fisheries as much as you do over straws. But indeed, don't invalidate. Say "if you like X, you might also want to do Y which has an even greater impact"

No matter how much we fuck it up, this rock will always be more liveable than anything we can realistically find elsewhere. This planet is our spaceship, we better start treating it like one.

As pointed out above, if you hate plants, you should eat as much meat as possible. Every kilo of meat represents at least ten kilos of plants eaten by the animal.

IIRC, this actually happens. When the balance is disturbed, the mushrooms go wild and destroy young sapplings. Could be I recall incorrectly and it's actually other species. I cannot recommend The Mother Tree enough, it goes into great detail of the history of research into this

And we are still increasing the rate at which we are making it worse...

So, "express network" instead of "highway". But other than marketing/communication, I didn't see much concrete suggestions of how to make them more inclusive.

Buffalo weren't eaten to almost extinction. And they don't give birth to 10 calves at a time.

...any economic system that does not take externalised costs into account. This is not unique to capitalism.

Yeah, I'd be quite surprised to see large increases in tourism anywhere in a +4° world...