I don't make that assumption at all (and I don't agree with it either). As I wrote elsewhere:
What I can't agree with is applying sunset clauses to laws that are intended to last. The solution to "Some laws are bad" is not "Let's make laws last for less time and then renew them!" it's "Let's make better laws". If a law is so bad you can't bear to enact it unless it is automatically repealed in 5 years - it's probably not a very good law. All this accomplishes is feeding short-termism, allowing politicians off the hook for their crap. "Hey I passed a law! (But don't worry it won't do any real harm because it'll be off the books before we see the consequences)."
Sunset clauses increase legislative overhead. There are two outcomes from this that I can see:
- the politicians are overworked so they are able to produce fewer laws, and so fewer laws (bad and good) are passed
- the politicians are overworked so they are less able to usefully debate/deconstruct laws, and more bad laws are passed
From your post it sounds as though you are advocating for position #1 - that is by making politicians revisit their laws, fewer laws are passed and so the bad laws will be reduced. However, if we apply sunsetting to everything then we also lose good laws. If you think this is on balance an optimum solution then sunsetting is a strange way to approach it - you can have the same effect by simply reducing the numbers of politicians*. That also has the benefit of saving money.
(* the Constitution may have a problem with this - but that's something that can be dealt with when you sunset that and revisit it).
I fall more on the side of position #2 in that I want elected representatives to spend their time doing maximally useful work. I do think there are probably too many laws, but that the most efficient way to deal with that is through progressively revisiting and repealing those that are deemed counterproductive (by the same debate process as sunsetting). I would argue quite strongly that such review should be carried out.