Earlier quoted context omitted.
if you infinite scroll, you'd also need some sort of url update so that you can always copy the url, and get back to this scroll position. i hate sites that have infinite scroll, but never allow you to "save" a position in the scroll to come back to in the future.
That's my point: most search results are ephemeral, and Google/DuckDuckGo results certainly are.
Granted, there isn't really any use in archiving ephemera like search results and frontpages other than notarizing odd patterns to show your friends or blog about, so the problem really lies in the interaction of web archival with infinite scrolling in general: comments sections, for example, can only be conveniently archived in their entirety without scraping if they're paginated and nothing is unloaded by default.