Wow, arborist talk on this forum? I'd almost given up hope.
Tom, Russ Carlson did some consulting work on a tuliptree in MD, deciding its fate to removal after 200+ years. See Liberty Tree on his site
www.tree-tech.com For the Biltmore folks to trash theirs so soon in their life shows that they do not understand the ease of maintaining trees thru middle age. They have a staff arborist and don't contract, so he may not be presenting the options in a saleable way.
jps, the maples in tosa my home town sound like they need some good PR and risk assessment. An article in the local paper about the benefits they provide may get peole to take a new look at them. A savvy underemployed arb like yourself may want to ID the canker and measure the decay on the first one they plan to cut, to see if you agree with their criteria. A sample budget showing years gained by dollars spent on mtc. might be useful there.
"Aren't the trees planted or left in the urban environment for the enjoyment of people?"
That's one way to look at it. The other is to see that trees came first, and for people to survive we must make sure they last.
"Is it so bad if people want a lawn, swingset, pool, sidewalk, or view etc. and shorten a trees life to make their own short life more enjoyable?"
Excellent question. My answer is no, it is not bad to remove a tree IF a higher benefit is gained, and tree removal is the best way to gain it. Only after people see every benefit the tree can deliver to their property and lives and consider every way to make that tree work for them can they make an informed choice about how to manage that asset. If cutting happens before the owner is informed about tree care options, that cutting is not done by an arborist, no matter how many ceu's he has or how much gear is on his belt.
I'm saying what rocky said; just using a few more words.