He only made 15 significant signings while here (signings for the first team and excluding deputy GKs).
Lukaku
Barry
McCarthy
Deulofeu
Eto'o
...all quality
He also brought in Holgate and Cleverley for next to nothing and they were decent in their time here.
So, spending a fraction of what was available to Koeman and Silva, he had aboiut a 50% succcess rate in signing players that could do a job here.
If that had been replicated over the last 6 disastrous years since Moshiri arrived we'd be in a very different position than we are today.