All this debate is great, but let's simplify this a bit and look at the realities in play here:
1) If my good friend "Rob" and his teamsters at UPS decide to demand higher wages and threaten to strike, what is UPS going to do? You really think the suits are gonna put on a brown uniform and go drive those trucks? Do you think the shareholders are going to let the company go under? The residential customers want their toilet paper and may bypass delivery and to get it locally at a modestly higher price. The customer has now altered a very necessary purchasing habit bypassing the delivery service. Yes, UPS has a problem now, and may be an even longer term problem later. But, the UPS drivers don't have that much leverage either because there are very large obstacles to starting their own private delivery business to replace lost income. It is in both parties interest to work something out.
2) Now if my friend "Bob" and his arborist union decide to collectively hike prices and refuse to work for less, you know what's going to happen in the residential market - and by the way this is irrespective of whether the tree company itself goes under or not? Only the hazardous trees are going to get any attention. For everything else, most homeowners are going to 1) say let it die and fall and I'll go buy a saw and deal with it on the ground; or 2) say let it die and fall on something valuable and I'll get insurance to deal with it; or 3) they will attempt to take it on themselves; or 4) they will find somebody of adequate skill possibly with a proper license and insurance who is not part of the arborist union and who needs to feed their kid and they'll get them to do it for a lower price. Fortunately for the customer, and unfortunately for us, the barriers into this business aren't huge and those people aren't that hard to find according to the disussions out here on TB.
I can step out of my house right now and see at least 10 large dead trees that the residents have no interest in dealing with. They have told me as much and are not interested in paying for removal.
So .... where did that leave you? I know where it left the trees. I just don't think arborists have the leverage that UPS drivers have. Maybe I'm wrong.