[diffeomorphism]

Can you give an example? For many things (software, hardware, buying things,...) older resources might still be valid but dated. For more settled subjects, e.g. encyclopedic, I also have not had Google be worse than Bing.

[pessimizer]

Google results didn't start to decline to be worse than Bing, Google results declined irrespective of and without reference to Bing. Google results are far worse that Google results once were.