Having ridden DI2 for over 10 years, in the Canadian winter, with salted roads, I have to believe you’ve never used/maintained/serviced an electronic drivetrain.

The mechanical parts will fail as equally quickly - in the same places - if not maintained.

I’ve not yet had an electronics failure on my three electronic drivetrains. Mechanical bits will wear out as per usual.

Until the recent influx of low-cost electronic group sets, the ones on sale from SRAM and Shimano were high-end enough that they were/are incredibly reliable with the exception of the first generation external Di2 Dura Ace battery which had a poorly designed mount that would indeed cause issues over time. The internal battery remedied that issue.