Because it'll cost a wedge to replace a management team that, under current economic conditions, people would be loathe to spend. If someone comes in, they wouldn't be charged with getting promotion - that's not on Dickov's remit either - instead we'd be getting someone to keep us up, something which wouldn't be beyond Dickov for some weeks yet.
If we keep Dickov, we will go down, thus reducing the already diminishing budget. So we might as well cut our losses now.