...because stay-at-home/shelter-in-place has been working in CA.
So while the measures have no doubt had an impact on slowing the spread, the models predicting dire outcomes were also quite clearly inaccurate, in some cases by at least an order of magnitude.
The US does not have the testing capacity per capita at the moment to avoid an uptick from a full reopening.
Denmark, Austria, Germany and others have already opened various schools and businesses, but with lots of restrictions.
Obviously the situation in California has stabilized. The goal was never to get 0 new infections and 0 new deaths. The goal is only to keep the transmission rate low enough to avoid overwhelming the healthcare system. And that has been accomplished in CA and CO and many parts of Europe and the US.