Anything in this world that has survived for
a long-time, had to be fit to withstand selective pressures. So look at
what existed for long time, that's probably has properties to adapt
well.".
This seems confused and and misguided.
All it means is that it survived the selective pressures to which it was historically exposed. It doesn't mean they were the best of all possible species, just the best (given the environment) compared to the others at the time, solely at the task of making more copies of themselves.