Google's John Mueller was asked on Twitter if a site would remove an AMP page, would that result in the ranking of that specific page to drop in the search results. John Mueller said "probably it [the search ranking position] will remain the same" as it was when it was an AMP page.
John did have a caveat that "there are subtle effects like speed, but depending on the page and query they might be minimal." So it is possible you might see a ranking decline, a small one, if the speed is a huge difference but as we've been saying for a while now, the query ranks supreme to ranking that the speed of a page.
Here are those tweets:
Probably it will remain the same. There are subtle effects like speed, but depending on the page and query they might be minimal. Why move away from amp though?
— 🍌 John 🍌 (@JohnMu) August 26, 2021
Many publishers have already removed AMP pages so maybe it is time more try?
Forum discussion at Twitter.
