Duplicating everything is unnecessary. Duplicating the thing which is foundational to a groundbreaking discovery is necessary. Beyond fraud there could be just an honest mistake or some fluke confounding factor.
Maybe there should be a "reproducability risk" metric, calculated with the transitive closure of all published results that reference a paper that has yet to be reproduced. This could help researchers calibrate how much they should trust a result and indicate when a foundational paper really needs to be reproduced.
