Interesting discussion on the SABRE forum which I would agree with, to wit, the maintenance of the bridge was less of an issue than maintenance of the river, which has meandered very much over the decades.
I suspect the primary problem was the direction of the current, having shifted from south to north to at best, southwest to northeast past the bridge and in some instances probably approximating west to east. On the 1870 OS map the main river channel was in the middle, and the main arch section was built over that within 15 years or so. Even by 1903 the main channel was no longer under the arch but the shorter link spans to the east, and this was still the case in the 1960s but with an additional channel formed to the west.
I'm not sure that Moray council is financially sound enough for both substantial river works and now bridge works as well.
I think in the short term a temporary light duty crossing could be erected a short distance upstream, say between Bogmuir and Bow Bridge, and if it was limited to pedestrians and cyclists, there would be no great need for strength. Even the traditional Bailey Bridge would be more than up to the task.