Link List PR trades

[eman]

I composed a tightly constructed, well-researched, judiciously thought out thread about Gooogle PR, and then lost it in the ether |pissed|

Anyway - the essence of my ramblings was thusly:

Are PR trades truly useful for Link Lists?

For my own part I'm not sure, since the very essence of a link list revolves around link trades. But I would immediately stress that I am in no way dissatisfied with the PR trades which I have established (they're all good people ).

The essence of what I'm getting at is this:
If PR trades are so beneficial, how come these LL don't go in for them?
link-o-rama
richards-realm
tommys-bookmarks
drbizzaro
dangerdave
jurbi (DD again)