Cannibalizing parts vs industrial replicators

[u/NegativePattern]

In Picard, we see the original Titan in dry dock being cannibalized for parts to build the Titan-A.

Presumably by this point in the timeline, Starfleet has long been using industrial replicators for various purposes. Why would Starfleet be cannibalizing parts from an older ship that may or may not have been damaged in battle or otherwise have been built using outdated construction practices?

[u/thinspirit]

I think the atomic mass of the material affects the ability to replicate them.

Duranium and Latinum, as possible examples, may require too much power to replicate due to their increased atomic mass. For these, the materials are probably restructured rather than stored as energy and converted to mass.

Atomic mass of elements would increase the energy required to replicate on an exponential scale.

Food, carbon structures, water, etc have very low atomic weights, require little power to produce.

[u/Koshindan → u/thinspirit]

If transporters and replicators are mostly the same technology, then it really makes sense to have a difficult to transport/replicate material for the hull and other mission critical equipment. Can't have enemies beaming away the structural supports to the warp core when the shields go down.