Triumph of the Weak

"Weak" verbs -- those that form their past and pluperfect by adding "d" or "ed" -- have long been taking over from "strong" verbs -- those that form tenses by changing shape in one way or another.  Here's one new to me, from a NYTimes story about renovations at the Gene Autry Museum (now Autry Center) in LA:

At stake is the mythology of the American West — a founding myth at once great and fearsome, inspiring and rived[.]

What happened to "riven"?  The verb used to decline "rive, reft, riven"  -- similar to but not the same as "drive, drove, driven."  As in Ezra Pound's great lines:

What thou lovest well remains,the rest is drossWhat thou lov’st well shall not be reft from theeWhat thou lov’st well is thy true heritage

It's a strange old word anyway -- I don't know why the writer chose it over "divisive" or "wounding" or etc.  that everyone could get; but as long as it's used, why not use the old form too?