Anything rare enough not to be on the net in some form or another isn't gonna just get stumbled on in a record shop bin. May find it on...wait for it...eBay(which still counts as "the net")...or in a collectable store with a decent pricetag attached to it. People really underestimate the internet.
With that said, millions of records aren't on the net. The reason being is THERE'S ONLY A FEW PEOPLE ON EARTH WITH THEM AND THEY'D LIKE TO KEEP IT THAT WAY RATHER THAN SHARING. that means they won't put them on the net, or leave them at a thrift store or in a record store for an extra buck off the new Rick Ross CD they're picking up, lol. But on youtube alone you can find recordings that only 100 copies were pressed of. And sometimes when you stumble on them they only have like 12 views!!!
Keep underestimating the internet, lol.