speaker wire deteriorates?

["itsme213" <itsme213@xxxxxxxxxxx>]

I installed a bunch of in-wall speaker wire about 5-years ago when building
my home. I used a decent speaker wire from Home Depot. Unfortunately I ran
out (of both wire and energy) and had the security wiring company run the
speaker wires for last speaker pair.

Now it seems I have to crank up the amp quite a bit higher than before for
that last speaker pair.

Does speaker wire deteriorate that badly? Would they have installed
something really crummy?

Thanks.