Although "infant formula" is better than evaporated milk, it is not hugely
better.  Let's not give it more credit than is due.  In an emergency where
neither breastmilk nor infant formula were available (floods come to mind,
also getting stranded somewhere away from civilization with a non-lactating
mom), evaporated milk formula would be the most appropriate substitute.

The risk of botulism would exist, but it always did, and most people my age
were raised exclusively on evaporated milk formula, made at home.  (Those
of us who survived, that is.)  The chances a baby would be hurt by fresh
cow's milk are greater, and even factoring in the severity of the risk of
botulism, I would still choose evaporated milk formula in an emergency if
it were available, rather than fresh milk.

In a non-emergency situation, if breastmilk were denied to the baby, I
would always choose infant formula.  But I think of it as a slightly
improved evaporated milk.