There was nothing else wrong with the blanket except the frayed ends. I figure it was perfectly salvageable with a minor hem job.
I cut off the frayed ends...
Folded it over and pinned it...
And gave it a quick stitch on the sewing machine. Start to finish, the project took 40 minutes (part of which was taken up winding a new bobbin and finding a fresh sewing machine needle after my usual one bent).
I washed the blanket and hung it to dry.
The blanket is obviously shorter than it was, so it wouldn't tuck under the mattress like it used to. I had to turn it sideways, where it's still a bit short. But you know what? Who cares. I have a feeling we'll all be mending a lot of things in the future, so this is just practice.
"Use it up, wear it out, make it do, do without."