I opine that a balance has to be struck regarding the type of work one does. I am a bit of a purist at heart and would prefer to see only necessary work done, but as pointed out, a firm could go bust.
(also am inclined to removing a tree altogether rather than trying to keep a large tree small through regular hard core reductions, for example; and replacing it with a species suitable for the size and nature of the area in which it is to grow, where at most a bit of maintenance pruning is sufficient)
I think it is bad for morale if tree people are doing work that goes against the grain. We have refused work that would break our hearts, although we choose carefully, such as if someone had their tree mullered years ago and wants a repeat (mainly pollard style of things), and the regrowth permits a more creative reduction/thinning that will leave the tree with a somewhat decent crown, we advise the client accordingly. If they insist, we generally will do the work.
Change comes slowly, more often than not, so patience with elevating peoples awareness of trees (biology/pathology) may prevail! Meaning that if tree people keep trying to educate laypeople, gradually people may shift to making better decsions regarding their trees.
Despite refusing work, or advising clients that what they think needs doing can actually result in what they are afraid of, or that it really is not necessary and the tree is best left alone, or recommending work that will give them what they want (often more light) without compromising the trees aesthetics or structural integrity, we have managed to increase both our client base and turnover. Last year, we were booked a month in advance, at a minimum, for the whole year, with perhaps a week in total in down time (after New Year, and 2 day drought during holiday season).
Often, laypeople have never considered that a tree is a living organism that responds to its environment, yet alone will endeavour to recoup the energy lost through removal of material, or the energy required by the tree to seal wounds and survive human impact. Upon finding out, many a person lookes upon their tree(s) differently, and, alas, many a person does not give a toss, such as it is.
(perhaps they should be charged what we refer to as 'wanker tax')
One positive thing that may come with a slow down in the economy: many a person will not easily part with their cash to have superfluous work done to their trees!