If you're confident, what features don't they have?
I subscribe to all their products so I can verify this :) I'm not sure why they don't have C# or C plugins but my guess is that it's because there's enough extra work in those IDEs that they want more money for them. Rider contains the ReSharper backend, which is a completely different application from IntelliJ.
The thing is, I’m confident in saying the plugins don’t replicate 100% of the feature set of PhpStorm or WebStorm either, but I’d defer to someone from JetBrains who has first hand experience.