There was a conversation recently spotted on Twitter related to some webmasters and SEOs which are deliberately making sure that their websites won’t be mobile-friendly in the apprehension of losing their rankings when they are switching over to mobile-first indexing. Their argument is that if they are not ready for mobile-first indexing, Google might not switch them to that process, and their rankings should not change.
See those tweets
But John Muller of Google viewed this as a bad strategy because you would lag behind when your competitors make their sites better. This isn’t a good idea to employ such strategy intentionally.