First off "banning" something just makes it more desirable not less
but if every AR in the country disappeared, a person who wanted to
kill a lot of people would buy a cheap AK47 clone or a Mini 14. That
is basically the same gun down range. The AK actually shoots a bigger
bullet but the ammo is just as cheap and there are plenty of
magazines, up to 100 rounds or so. That was the evil gun in 1993-4. It
just fell out of favor.
I bet in the private market they were not getting more than $250 300
for them a couple weeks ago but I am sure they are more now.
You really don't see a lot of those old thumb hole models around but
they sold a couple million during the ban so I am sure there are
plenty gathering dust somewhere.
Would restricting their sale make the anti-gun crowd happier? Yes. It's not a matter of prevention,
it's a matter of perception.
How do you really restrict the sale of existing guns? If you simply
say they are not legally transferable, a lot of people would sell them
under the table. Most people are not going to just throw away several
hundred dollars for an AK/AR or well over a thousand for my M1A.
Actually there are AR platforms that are well over a thousand too.