The dollar shave club not only sells cheap shaving gear (compared to gillette at the supermarket) but also sells reassurance that the gear isn't crap, which I think many consumers fear about no-name alternatives.
They will probably only know Gillette and some no-name they tried once and hated. If they were to see Dorco on Amazon most consumers would put this into the latter category. On the other hand, DSC has good enough marketing to convince many consumers that DSC are in the Gillette category for a fraction of the price.
That said, stuff like bic is terrible.
One thing I'm sure of: A good sign of a superior product is that it doesn't need monthly replacement.