usage of ‘indefinite article + proper name’?

I’ve just come across this sentence.

“Only an Albert Einstein could have the wisdom to reject an offer to become President of Israel because he argued that he did not have enough experience in working with human beings.”

In this context, what does the phrase “Only an Albert Einstein” mean?

I’m well aware that the indefinite article can be used before a proper noun, and that the meaning is usually ‘a person who is similar to the referent of the proper noun.’

But the example above is a bit tricky for me. The writer chose the past tense, and so it seems that he/she is really refering to the Albert himself.

A well-known person, when epitomized/ objectified with an article before the name, refers to the epitome or the object itself.

An Albert Einstein = A person of Albert Einstein's kind/ caliber/ stature ...

HTH.