No, that isn't true. The barrier-to-entry is low, therefore the competition is extremely high.
To learn WordPress, you'd want to visit the WordPress codex that you can find over at wordpress.org.
There are so many good resources on the internet that a search in your favorite search engine will give you an abundance of results. My favorite site probably is perishablepress.com. WPBeginner is also a solid resource.
And there are many books. If you do a search here in the forums, you'll be