How far back can the average europoor trace their ancestry?

Depends on the region. You can usually go a few centuries, using church records.

>>135613429
Tracing directly no, even though a blood relative is tracing the history of my family but I know for sure that my ancestors lived in Sardinia since thousands and thousands of years ago
If I had phoenician ancestors they would have lived here 2500 years ago
If only Sardinians even 6000 years ago
Italians can say something similar probably about themselves

>>135613301

I could trace some of my ancestors back to 1700, the rest of the records were detroyed during ww2 according to my grandparents

As far as I know the family has always been from Sardinia, from Barbagia and Campidano, but I never made any real attempt to track it past my grand-grandparents.

To the 600's.
Families that came to the US in 1600's often had noble relations with documented pedigree.
E.g. - I'm a Plantagenet.