The AD8610 is not remotely competitive with the OPA189. The proper comparison is with parts like the bipolar OP77, OP177, AD708, and similar (1) which have offset voltage drifts of 100 nV/C compared to the typical chopper stabilized amplifier's offset drift of 50 nV/C.
What these parts all have in common is that their offset voltage drift is dominated by self heating and the immediate environment. Under ideal conditions, chopper stabilized parts have a lower drift but without thermal baffles and without high load resistance, they all perform equally poorly; thermocouple effects will dominate. With the AD8610, the difference in performance would be much less.
Where precision bipolar parts cannot compete is with lower flicker noise since chopper stabilization removes it.
(1) Since trimming the offset voltage of these types of precision bipolar operational amplifiers reduces offset voltage drift, even parts with higher drift are suitable if offset nulling is used.