Contrary to what Trump says on his Twitter feed, media organizations are very wary of giving anyone and everyone anonymity to make attacks. Reporters push sources to put their names on quotes or at a minimum to narrow the anonymous descriptions to show as much of who these people are (and why they are saying what they are saying) as possible to the reader. Media organizations -- the credible ones at least -- are hugely averse to letting people take potshots without their names attached to it.
Given all of that, it's telling that the Times was willing to extend the cloak of anonymity to this author -- especially, again, because of the stakes and the target. This is not a decision made lightly. That the decision was made to publish it should tell you that this isn't some disgruntled mid-to-upper manager buried in the bureaucracy. This is a genuine high-ranking official. A name most people who follow politics -- and maybe some who don't -- would recognize. The Times simply wouldn't do what it did for anything short of a major figure in Trump world.
https://www.cnn.com/2018/09/06/politics/new-york-times-op-ed-donald-trump/index.html