There are a sufficient number of auxiliary bishops out there I’m certain.
Back in the day, auxiliary bishops were needed to administer confirmation to students in every parish of the diocese, that is no longer necessary as priests often administer it.
And even back in the day, here in Pittsburgh at least, one of the parishes had an auxiliary serving as a pastor of a parish in addition to his auxiliary duties.
I’m pretty certain that there is a sufficient number of these auxiliary bishops, if the ordinary of the diocese is in need of more help in the administration area, ordinary priests and lay folk can certainly help out as well.