The basis for the LA Times suit was "The Plaintiffs allege that Defendants' copying and archiving decreases revenue from ads and from accessing archived materials." Road & Track doesn't archive 30 year old articles and so derives no revenue from them through ad sales. There are times when the complete reproduction of an article is required for educational purposes and scholarly research and so is covered under the Fair Use doctrine.
". . . and for accessing archived material".
In the example you are arguing, note that Road and Track sells back issues, therefore they do archive and make available for sale past issues of their magazines, and derive revenue by doing so. As to whether or not available issues go back thirty years is a red herring - the copyright stays with the owner, and it is at the sole discretion of the owner as to how the material may be commercially used. Just because a publisher chooses to no longer make available a copy does not, in any way, diminish the rights of the copyright owner.
Jon is responsible for all copyrighted material that appears on his commercial site. Therefore, as a commercial forum, Jon would be held liable under Federal law for any unauthorized use of copyrighted material. Furthermore, any burden of proof regarding the fair use argument would fall to Jon.
Again, I stress that the likelihood of repercussions is slim, but the precedent of LA Times v. Free Republic opens the door for that. The act of defending such arguments would fall to Slim, and I suspect he doesn't want to go there.
So the clear and obvious way of continuing to legally post what I think is often some nifty stuff would be to get the written permission from the copyright holder to do so.