Read it again, he was talking about the course returning, not how long it takes to graduate.
The Army has always broken up the Ranger units after every war, until recently, the arguments go on and on within the services.
I read it. More than once. The part you point out ALSO highlights the evil of shutting the program down.
You can't re-establish it "immediately". You can start to do so right away, but actually getting it up and running takes time. Then, students have to graduate. That also takes time.
All that time, is time you don't have enough properly trained personnel, when you desperately need them.
the arguments go on and on within the services.
Yes, they do. And the argument that training "special" troops is too expensive is what we call "penny wise and pound foolish". And that expression is obviously quite old ... people in various walks of life have exhibited that particular folly for a long time.