> What people want generic methods for is to do deeply nested call chains

I don't see that as the only use of generic methods.

The example in the article is a "Map" method that transforms e.g. a List[A] to a List[B], by taking a function that takes an A and returns a B. To be able to transform a list like that is a useful operation.

It was possible to do the same with a global function like MapList but the syntax is nicer if you use methods. You don't need the type in the name (function MapList vs method Map) and it is an operation on the List after all so list.Map(..) is nicer than MapList(list, ..).

The generic methods that have been added are essentially just syntax sugar. You can now use method syntax in cases where you could equivalently define a function. They’re not the fundamental extension to the type system that some people have been asking for (and probably will never get, because there’d be no reasonable way to implement it).