> so it doesn’t make sense to track its provenance back to its original authors

The legislative process is inherently collaborative in a way that's ordinarily undocumented. Who introduced an amendment and who supported it are entirely separate. Someone who introduced language can wind up not supporting it because of where the mix of trade-offs winds up.

At the level of a bill, knowing who wrote language matters. At the level of law, you should only care who voted for it. (I'm not even tackling the inherent subjectivity in tracing e.g. language in the CFR to specific language in a bill.)