Why do you think we have never been able to isolate it? We do so many thousands of times per day.
Go here and you can access a database of over a million sequenced Covid genomes:
https://www.ncbi.nlm.nih.gov/sars-cov-2/
Not a scientist, but my guess is perhaps we’ve been unable to isolate it because it is something that does not occur in nature.
Physical isolation of actual specific covid-19 virions, troll-boi.