Perhaps, Jno, the argument is that Rembrandt and Rodin would have been displaying their exceptional talents in order to create a REPRESENTATION of a bed, rather than making the bed itself (or, more accurately, leaving it unmade!).
Tracey Emin would claim that her art lay in the 'concept', rather than the 'creation' of the work. Such an idea is valid for, say, Norman Foster (as he only has the concepts for buildings, rather than actually building them) but, to me, it appears a little more tenous in relation to Ms Emin's work.