And following the change of speed limits is huge public backlash, leading to a quick repeal of that reduction.

Nah, that would defeat the purpose. This baby is long term.

The slow speed limit is bad, even beyond simply being annoying. It would be expensive, or impossible to truck perishable food across large distances. For example, to bring oranges from Florida to where you live would take 10 times as long.

On the other hand abolishing speed limits would make driving very scary.