The point is, many people cannot do runs not because they don't have the capacity to or they just waste too much gold in boosters, but because they simply don't have someone to buff them. They still do the runs when they can, but it's not in a non-stop fashion that makes you enjoy the game more. Basically, having no buffing partner doesn't allow some players to play the game as they prefer and how a big part of PvM-time should be occupied.
DC Run with sura is an exception to the rule I mentioned, however, at this stage of the game, most high level players have access to characters with which they can do the run. For example, Silvester who was just talking here had also a lv115 Sin. Moreover, with the new lv100 helm, new pvm armour and fire shoes, while pushing a lot the damage, maybe suras can do the DC run solo, but as you say it doesn't compensate. DC is one of those cases in which cooperation compensates, since if you take a 90- level partner with you he can assure that the first 2 bosses drop a changer and stone craft 99% of times, increasing the "pie" of each run by 55-60kk.