Testing was considered key to defeat the virus and for re-opening. It still is, but can't be if cases get out of control. An example of how testing helps to slow the spread: Someone works in a restaurant and gets sick. They get the test and it is COVID. Now all of their co-workers also get tested. So do known customers. Some are positive and get sick shortly thereafter, some are negative. And you can reduce the spread by knowing that and sending those positive cases home to quarantine before they work another shift. You might even find an asymptomatic carriers and slow the spread by keeping them home instead of all over town doing their normal thing.
Testing alone isn't going to stop the spread entirely unless the caseload is very very low. The effectiveness of massive testing breaks down if the outbreak is so rampant that it effectively overwhelms the contact tracers. If it takes the contact tracers assigned to your case a couple of days to get to you, and then another couple of days to track down the employees and customers at the restaurant, then you have largely missed your window of opportunity to identify cases before they spread it in turn. The contact tracers are now always "one step behind".
And that leads to the last point, which is that we still don't have what we need with the testing. We need rapid testing. That was always the goal, but the early rapid tests were total unregulated garbage. Some are still around, but I can say that at my wife's hospital, the result from their rapid test machine is only considered preliminary. The result is confirmed only by a nasal swab that gets sent off to the lab and analyzed 3 days later. We still don't have widespread, accurate, and easy rapid testing. Imagine if you could reliably test everyone in a restaurant before they start their shift? Or you could require all employees of a big office building to get a rapid test once a week? Or before boarding a plane? There's no way that wouldn't help.
Masks are another issue entirely. They only work if people use them. Even then, they are not 100% effective. And a lot of people don't wear them, even in Europe. France just had a mask burning protest. Italy had a big protest of renewed lockdowns. The US doesn't have a monopoly on covid fatigue. Also, the weather is turning. We just had ten inches of snow here on Monday. It's been long suspected that COVID survives longer in colder temperatures, which would make it more virulent. But as Weatherdemon said, we don't really know.
I'll grant that masks can give a flase sense of security. They objectively work great at preventing spread from person to person while standing in line at the grocery store. Less so for two people sitting and talking face to face for half an hour. They are still better than nothing in that scenario, but people might engage in the latter thinking they are better protected than they are. Even so, I think they are a net win.