It's time for new rear tires. I looked through the (36 page!) thread on tires and wheels to make sure I wanted the Yokos. (Thanks for the advice, JoeS!) They are quite comparable to the original Dunlop Enasaves, except that they are about 10% less efficient. I can deal with that, especially since they're typically a lot cheaper. (Tire Rack seems to be the only place to buy the Dunlops, at around $156 each.)
So I was searching around for the Yokos, which are discontinued but still available at resellers, and found this:
https://www.ebay.com/itm/2-New-Yokohama ... 3395685885
It's the Ebay store for SimpleTire, and they're selling pairs for $178, only $89 each, free shipping to continental US. They have one pair left as this is written. I suspect the 175/60R15 is a very slow mover. It might even be that it only fits our cars, else why sell them in pairs instead of sets of four? So they're doing an Ebay clearance to make room for inventory that moves.