I don't fly, so I'm just kind of curious if, in the US, we've reached the point where it's cheaper to mail your luggage to the destination if you have time.
It may be close... my only point of reference is I recently shipped an older 50 lb Mac Pro from Oregon to the Midwest (I forget where, exactly) and that was $42.00, with insurance, through USPS Priority Mail. I paid online which gives you a discount, but shipping rectangular boxes is cheap.
Depends, for things like bikes (which cost even more to fly with at most airlines) it sometimes makes sense to ship. I don't think it's worth it for most bags though, $25 (common fee) is a pretty low price compared to what it costs to ship 10s of pounds. I guess maybe ground? But yeah it's expensive to ship things too.