It’s a question of incentive. Right now, supporting software is costly for a long time because very little attention is given to making software maintenance cheap.
That’s why it’s reasonable to force company to offer long term support after sells. It means they will have to design software so that it remains viable with a minimum of changes for a long time. Things that don’t make sense today because of their costs like formally proving code and design suddenly become important and as there is an incentive to make it cheaper to be competitive we should see new investments in this field which is currently quite neglected.
Overall it’s a net gain for all of us. In exchange for marginally more expensive computers for a bit (or less profits if that’s how companies want to compete), we will end up with safer more robust software and longer lived appliances.
It would be a major step in the right direction. As someone trained as an engineer, I still think that the software industry tolerance for subpar under-engineered and tested solutions is shameful.