Small clarification. I wrote:

At the end of the day it's no different from taping an album you've borrowed from a friend.

What was in my head, but didn't make it to the keyboard, was

it's no different from taping an album which is no longer available that you've borrowed from a friend.

I agree completely with the comments about pirated versions of currently-available albums. Many, many folk albums currently aren't. I've acquired several albums without paying - either by downloading or by borrowing tapes from friends. Is there any other way I could have got hold of those albums? Barring a lucky find in a second-hand shop, no. Will I replace my mp3s with legit CDs, as and when legit CDs become available? Yes, finances permitting.

A great example is the Within Sound box set, which I'd dearly love to own. Unless and until it's reissued, being able to get hold of the tracks which are in the box set and aren't available anywhere else doesn't seem like such a bad thing. (The relevant post is here.)