This is nitpicking his point.

But anyhow, you can buy large-ish burlapped trees but they aren’t as healthy, often die, and nothing close to a 100+ yr old estate oak tree or a decades old rose garden. You just can’t make it faster, transplanting plants that old will kill them.

You're moving the goalposts on his poor analogy :)

Most of the trees do just fine, and these nurseries will typically provide a warranty.

Besides nitpicking, even your original point isn't even true. You cannot transplant a 100 year old tree (which has not been constrained in size dramatically) and expect it to survive for any reasonable length of time.

You won't find a 50 year old American Chestnut in a nursery, lol.

And forget about 20k. If you find someone willing to sell their tree you're looking at at least 10x that for the logistics of moving a 20 ton root system.

You won't find a 50 year old American Chestnut anywhere lol, they were wiped out almost entirely.

You'll find it if you look hard enough. Whether the owner will let you dig up their entire yard is another matter.