My hart was always with one man Dxpeditions. From early stage of my HAM career I watched Eric SM0AGD, Jim VK9NS, Ron ZL1AMO efforts. Now their role took Nigel G3TXF, Vlad UA4WHX and Charles KC0W. When I started not only watching but also participating in expeditions, I made some one man DXpeditions too: SP9FIH/OA4, FO/SP9FIH, A35WE, 9N7WE, E44WE.
From financial point of view one man DXpedition is much cheaper and efective then multi person effort. Compare 12 000 QSOs made by one operator in 14 days costing about 3000 $ to 60 000 QSOs made by 8-10 operators in the same time and spending more then 40 000 $.
Last time I carefully watched and cheered Mark ON4WW well planed try to make one man Bouvet expedition to come true with goal 100 000 contacts during 3 month. Unfortunately amateur radio community voted for big, costly, short period expedition which can make probably 60-80 thousands of QSOs.
Look – 100 persons making small expeditions will give you 100 DXCC entities every 3 day in a year. When you group them to 20 persons big events it will give you 5 DXCC entities every 2.5 month.