Maybe a decade of decades. But it’ll eventually get there.
There’s too much infrastructure based on even units in imperial that would “turn into” a partial digit if forced to stay the same.
Example. 1/2"wrench would be the same as a 12.7mm wrench. And a 1/2-13 bolt would be a M12.7x1.9532 bolt.
That stupid conversion makes no sense, so we just use both. Eventually as we replace imperial infrastructure with metric, we’ll use more and more metric, and less imperial. Until eventually it’s all metric. Though a common structural lumber will likely still be called a “2 by 4” even though it’s measurements would theoretically be 35mm X 85mm. And nobody will remember why.
Other than that leaves a huge market for SAE spec bolts for use in maintaining the already imperial equipment. As it’s more cost effective to repair up to a point. So some company WILL produce those bolts.
Which is why we’re here with both types of units, and why it’ll be 100+yrs before imperial actually dies.