They probably did, but spear shafts get reused and the heads get melted down. A sword is much more labor-intensive and expensive to produce (not to mention hard

They probably did, but spear shafts get reused and the heads get melted down. A sword is much more labor-intensive and expensive to produce (not to mention harder to use effectively), so less likely to be recycled for it's constituents and more likely to be found in the archaeological record.