How much does it cost to deal with this tree's never been pruned and it's out of control?

Priced by climbing time and debris volume, and a neglected tree is expensive on both: there is a great deal of material, much of it small brush that is slow to handle relative to its weight, and there is no easy path through a full crown. Deadwooding a large tree costs more than it looks like it should because the climber has to reach the entire canopy to do it properly. A multi-visit plan costs more in total than one aggressive job, and that difference is the price of not damaging the tree. Cabling adds hardware plus a standing inspection obligation every few years, which is an ongoing cost, not a purchase. Dormant-season scheduling in late winter is often both cheaper and better for the tree.