Since the chip is meant for inference but not for training, in theory you only write to the Flash once or twice. In this case data retention is a more limiting factor than wear.

For digital storage the data can change quite a bit before a 1 becomes 0 or vice-versa, but for analog even a small change can be a problem. So I don't know if we can extrapolate the typical Flash memory data retention number to the expected aging for this device.