Why were almost all of them scrapped?

Didn't ANYBODY after WW2 have the love of airplanes and the foresight
to buy at least one military airplane, especially since they were so
cheap? What were they thinking?! Did they not see the value of these
planes for future generations? Why didn't some civilians simply buy a
B-17 for $700 and park it in their yard? Land is cheap in rural areas.
These airplanes are so precious to me. I have loved the glory of ww2
fighters and bombers since the earliest childhood.

Another question: if someone had the money, would it be possible to use
blueprints to build perfect reproductions of airplanes like the B-17
and P-40?