No, that's not fantasy land at all, this is common sense, standard practice, and the default position if you are a tenant.
There was no urgency: If some expert said the tree was dangerous then it would have been cordoned off while remedy was arranged. It was costing nothing to inform the landlord/owner.
We are not talking about asking your landlord if you can hang some window flower baskets from your studio. We are talking about a contract clause on the order of "keep the f-ing yard mowed and the trees trimmed" between two big evil organizations where Statistically Nobody(TM) really cares.
I understand there's no urgency but regardless of timeframe it's just not reasonable to expect discussions to happen between government and a tenant in the way you think they should in the current regulatory environment. Nobody's immediate interest is served by doing it that way and everyone's interest is served by doing it the way they did except in this rare case the public interest and it blew up and became a "court of public opinion" thing hence the lawsuits flying every which way and the finger pointing.
If you want to see organizations act how you seem to want toward government then government needs to change. Organizations are unfeeling and sociopathic in pursuit of their goals. They are keeping the .gov at the maximum arms length possible, spreading liability all around, and letting these processes hum along and "fail" in dumb ways that are probably obvious to the people on the ground (but of course nobody will take on the responsibility of raising objection) because those failures are less terrible when they do occasionally happen than the kind of problems you'd get they didn't make it SOP to run the way they run.
The common sense you speak of has been implicitly outlawed by the high tax of liability that is levied upon it.