No, Zcash was not exploited.
The people who patched it were all top 0.001% of their field.
The methodology to find it is known and accessible to 0.01% of people.
The circumstances to find it were to hire a person whom already discovered an inflation bug 10 years earlier.
The circulating supply is following the predictable supply curve.
The Orchard pool is growing at a predictable rate consistent with the chain’s usage.
And even if it did get exploited (it didn’t), this is, worst case, similar to The DAO exploit in Ethereum, where 20% of the supply sat in the compromised smart contract, as opposed to the infinite mint bug on Bitcoin (21 million –> 184 billion).
Coming to your favorite coin next, but not Zcash.