… he is in the unique position to petition or speak with some authority to the pope and his equals - and actually be heard. Has he said why he is not doing that?
I'm afraid you have got your tenses a bit muddled here, Stubborn. For the ten years prior to 2018, ++Viganò
was well positioned to address the pope and his senior prelates, and he did so with regularity and with rather more bluntness, especially with regard to financial "irregularities" and sɛҳuąƖ corruption, than Benedict and those around him thought seemly. As a "reward" for his service, ++Viganò was moved out of the inner circle of Vatican City administration and made papal nuncio to the USA. When he continued to "misbehave" here, especially when his warnings about McCarrick and others were insultingly ignored, his pro forma resignation in 2016, required of all prelates at the age of seventy-five, was promptly accepted by Francis. Then in 2018—once, that is, the archbishop had located a place of seclusion from which, with the help of a few trusted associates, he could reveal what he knew without being "ѕυιcιdєd"—++Viganò went public with his inside knowledge of Vatican activities over the prior twenty-five years.
In short, everyone in the pope's inner circle has long been familiar with what the archbishop has to say. He himself has made plain that his target audience consists of what we at CathInfo might call those still-deluded neo-Catholics who haven't yet awakened to the fact that the religion they espouse is no longer the religion of their parents and ancestors. The fact that ++Viganò hasn't made a great deal of headway is a sad tribute to the diabolical success of the conciliar revolution.