There may very well be radios that are "worth" fixing after 10 or more birthdays but practically speaking once they hit the point of having failures, parts are secondary - someone has to troubleshoot and fix the thing and that right there puts any piece of equipment in a category of you gotta love it. Maybe a 2007 K3 is awesome enough to spend a few hours with it on the bench to restore it to operation. Most HF rigs aren't. For some folks the fun is in the thrill of the challenge - fixing and restoring things. I used to make a living doing that and frankly I could care less if I ever fix another one. I'd rather be working the radio than working on it. So the notion of "product support" becomes largely pragmatic - most equipment made in the last 30-40 years is just another commodity piece of electronics that has a practical lifespan. If you lovingly restore a 1990's HF rig, after all that the best it will ever be is a 1990's HF rig. OK, but not remarkable. The best you can expect is to run something long enough to exceed it's usefulness or your attention span, after that it's traded off or scrapped and on to something bigger and better. Save the valuable bench time and frustration for the few select pieces that would actually be worth it - distinct performance, intrinsic, or sentimental value.
Mark K5LXP
Albuquerque, NM