I don't think you should be downvoted tho. Reasonable and correct opinion from a (guessing) security professional.

The 20 year smart devices argument should be the norm, imho. We have way too much e-waste as it is. Although that would also mean that smart devices should include that in sales calculations.

The firmware flashing before EoL brings a tear to my eye from the elegance of a solution. Also manufacturers would have to stop with other anti-consumer practices like serialization and scrubbing identity markings, otherwise reversing could be too costly.