I'd also check that the engine steady bushes are in good order and the bottom of the jet hasn't walloped into the bulkead, bending it and making it difficult to operate - this often manifests as an ability to pull the choke out but unable to return it.

Don't buy a new cable yet.  There are two things I would do first.

Remove the core from the choke cable sheath and wipe it down with moly-grease (CV joint grease, garage door bearing grease, etc).  Also look at the cable routing and make sure it is not running near or against something "hot".  If that doesn't help, take a close look at the jet lowering choke linkage.  The later ball/socket choke linkages used on the Waxstat jets are generally problem free.  The earlier bent sheet metal choke linkages can become out of alignment to the point of binding and preventing the jet from going back up.  The fix is to remove the carb and tinker with it on the bench, bending and adjusting the link as necessary.

So, of late, after my car is running nice and warm, I push the choke back in--but the engine doesn't seem to slow down. I can pop the hood and manually 'retract' the choke, but am wondering if there is any fix aside from replacing the whole cable. Thanks in advance...