Tim - We save resources by eliminating extra connectors from every unit we make - millions of connectors, gold-plated contacts, etc. While the repair depot may swap-out an entire logic board for the sake of a fast turnaround, that logic board will be repaired... When and if we bin a board or component, it goes into recycling, not the landfill.
News - Still, soldered components greatly reduce the possibility of do-it-yourself repairs...
Tim - Our studies show a small minority did their own repairs when these components were socketed, while socketed and conectorized components have a higher failure rate. What price should the masses pay for the sake of the DIYers? I haven't had to carry an iMac to the Genius Bar myself, but I can't imagine it's a great way to spend a Saturday afternoon.