Doucoure and Godfrey were clearly Brands's signings (Ancelotti said as much). Digne and Mina likewise. Gomes has been a poor signing as has Delph. Gbamin has been massive bad luck. With Kean we at least get our money back (and make a small profit I believe). Rest of his signings have been freebies or small change.
So four good signins, two bad (although I could see why both were signed), one bad luck, one so-so. Not great but if he had been given the same amount of money as Walsh he would have done better. Assuming no outside interference.
We would also have had much better managers than the ones Moshiri has picked.
Having all that I don't think he's untouchable. I just don't think sacking him will make an iota of difference. After that it's either more signings by the managers (scrap the DoF model) or the next guy will face the same issues of owner and managers meddling with his job.