texts don’t have a source…so yeah…you can’t alt drop them from your project…
If you have some odd swapping to do… copying and pasting will be the away to go. there is no simpler way. Though if you got to swap something like text layer 3 onto 5, 5 onto 7… and so on. You can get by with expressions…
Pasting something like “thisComp.layer(thisLayer.index-2).text.sourceText” would swap the source text (AND NOTHING BUT THAT (no colors, sizes or anything)) of every text layer by the one 2 positions above it on your timeline.