300K tests / day is still less than 1/1000 of the US population. Considering that people will need multiple tests over a period of time, this is still only a fraction of needed tests.

Until an effective treatment is developed (or a vaccine), widespread testing, contact tracing, isolation are the way to go.

I understand that much of the delay is because key suppliers in the Far East were affected by control measures and by a worldwide surge in demand. That just means there needs to be a very high priority on building / rebuilding local (as in within North America) production. And of course, waiting weeks before submitting orders for PPE, ventilators, and other medical supplies ... which allowed other nations to get ahead of us in the queue for shipments.

(Funny how many people I saw laughing at #T-rump [President Trump] because he talked about bringing production back from overseas. Now we see that it is necessary, no matter where we stand on the suitability of the occupant of the White House. Expect President Biden to announce new initiatives to relieve dependence on foreign suppliers for critical items.)