I agree with Maffyoot:
in many contexts, infinite pagination is actually a hindrance.
Think about a list of 300 items, which I want to review, one by one.
In this case there is no “perfect search term” to use to shrink the list.
My favorite interface let me decide how many items per page I want, say 100, after which I can open the complete list in 3 tabs in the browser.
Having everything in a single page would make the list too long, and besides the problem of server processing resources / network lag, it would make it hard for both me and the browser to scroll up/down with enough speed and precision to any given desired line.
I would also have a hard time remembering the visual whereabouts of a given item in the page (that’s quite a problem with infinite scrolling in any context: a line which used to be “close to the bottom of the page” will be “close to the top of the page” after a bit more scrolling).
Otoh having 100 items per page, with many pages open, feels much more natural - just like one would browse, say, a book!
Last thing: all the nice “perks” which make infinite scrolling bearable, like allowing deep linking and spidering, currently cost a lot of development time, and many developers fail to grok the concept properly (or just are not given enough time/money for that), so we see a lot of bad implementations, which give us worse user experiences that we had before.
I still see plenty of sites that only allow a single sorting order in their search results, and have no support for facets/ drill down. Those features are much more useful than infinite scrolling…