It's been no more reactionary than most other nations in the world. There is absolutely long-term planning by the majority of states. To the extent that states are frantically changing their strategies, it's because we're learning more about the virus and how it spreads, and shifting our strategies.
Take New York, for example. Its high death rate can be largely attributed to Governor Cuomo's disastrous decision to force nursing homes to accept COVID patients from hospitals. He has since walked back that strategy, and New York continues to maintain a phased lockdown strategy with a structured re-opening plan with measurable criteria[1].
Governers Inslee, Newsom, and Kate Brown have been receiving (well deserved) praise by the media for their structured approach to handling the outbreak[2].
Governor DeSantis deliberately focused Florida's COVID strategy on nursing homes, deploying the National Guard to the nursing homes, and prioritizing testing resources in LTC facilities[3]. To this date, Florida has among the lowest deaths per capita in the Union, and lower deaths per capita than most of the EU[4]. As a result of this, even despite a recent increase in cases, their death rate remains mostly flat — especially relative to the same metrics in most other States[5].
Between March 16-23 (at the outset of the outbreak), every single US state ordered a state of emergency, 11 had stay-at-home orders, 30 activated the state national guard, and 48 closed their schools[6]. By as early as March 9th, the States were doing the VAST majority of COVID testing[7]
As of right now, 36 out of 50 US States have a lower per capita death rate[8] than France, Sweden, Italy, Spain, the Netherlands, and Ireland[9]. 15 States have a lower per capita death rate than Germany and Denmark, who have seen the best COVID outcomes in the EU. The US, to date, has administered more tests per capita[8] than Belgium, Australia, Ireland, Italy, New Zealand, Canada, Switzerland, Germany, Austria, Norway, and Sweden (to name a handful).
It would take the most uncharitable reading of the situation to conclude that the US member states have been any more "reactionary" than typical peer nation-states.
[1] https://forward.ny.gov/metrics-guide-reopening-new-york
[2] https://www.voanews.com/science-health/coronavirus-outbreak/...
[3] https://www.nationalreview.com/2020/05/coronavirus-crisis-ro...
[4] https://www.worldometers.info/coronavirus/country/us/
[5] https://twitter.com/paulnovosad/status/1279967210224705542
[6] https://twitter.com/COVID2019action/status/12421349564632268...
[7] https://twitter.com/balajis/status/1238574921346732032/photo...
[8] https://www.worldometers.info/coronavirus/country/us/
[9] https://www.worldometers.info/coronavirus/#countries