What does 'when the danger is over' mean in practice ? When it becomes zero ? When nobody dies of corona anymore ? If it is that, then the measures are permanent, and if not, what ?
That's an important question, and reasonable people can and should disagree on the exact answer. But the proper response is not to throw up our hands!
This question is not significantly more difficult than other questions that most legal systems routinely deal with, like "Precisely how clean does a restaurant kitchen need to be?" or "What exactly constitutes fraud/murder/etc.?" or "How exactly do we determine if a driver was under the influence of alcohol?" or "How educated and skilled must a surgeon be?"
These are all difficult questions with direct consequences on personal liberties, public health, etc. Many of them have fairly uncontroversial answers for a large portion of cases, but they also have tricky edge cases where reasonable people disagree. Legal systems ought to (and generally do) attempt to clearly codify things to handle the large portion of cases, while also having some process for resolving conflicts for the tricky edge cases.
It's simply not reasonable to imply that basic public health mandates in response to a pandemic is some new or uniquely difficult scenario for legal systems to face, and that because it's difficult, legal systems should do absolutely nothing whatsoever.
https://kingcounty.gov/depts/health/covid-19/data/key-indica...
That's just one page of many on that site, for just one county out of however many counties there are in the U. S. So I believe it unnecessary to act as if there are not easily-accessed answers to your questions.
The danger will be over as soon as COVID becomes nothing to be worried about. As soon as everyone who wants to can get vaccinated and as soon as everyone who can't be vaccinated don't have to worry about it due to herd immunity.
It's very simple.
A much better approach is to define an acceptable level and live with Covid, much like we live with the flu, cancer and other deadly diseases.
The US seems to be the most sane part of the world in this regard.
This is real, it's measurable and it's time-limited.