Evidence from spring and early summer 2021 matches Friedberg’s prediction that, even after COVID-19 vaccines were widely available in the U.S., many schools would still not be fully open and a substantial share of people would continue avoiding flying and normal social activities due to COVID concerns and rules.

1. Vaccines were widely available by spring 2021

• By April 2021, KFF reports that eligibility for COVID-19 vaccination was open to all U.S. adults and that a majority of adults had already received at least one dose (56%) or would get it as soon as possible, indicating broad availability and substantial uptake by mid‑2021. (kff.org)

2. Many schools remained closed or only partially open through the end of the 2020–21 school year

• Federal NAEP data for February 2021 show that only 39% of 4th graders and 29% of 8th graders were attending school full-time in person; 42% of 4th graders and 45% of 8th graders were still fully remote, meaning large numbers of students were not in open school buildings. (keyt.com)
• A Congressional Research Service summary of NCES data for May 2021 (still within the 2020–21 school year) reports that 63% of schools with 4th/8th graders were open full-time in person, but 79–80% still offered remote learning and about 40–45% still offered hybrid options, showing that substantial shares of students remained in remote or hybrid modes rather than fully reopened schools. (congress.gov)
• A cross‑state analysis of the NAEP school survey finds that in spring 2021 the average enrollment in remote or hybrid instruction was still around 41%, with extreme cases such as California where up to 97% of students were in remote/hybrid rather than fully in‑person schooling. (mdpi.com)
  Taken together, these data confirm that well into mid‑2021, many U.S. schools were not back to normal in‑person operation, matching Friedberg’s claim that “schools aren’t opening” even after vaccinations (interpreted more precisely as: many remained closed or only partially open).

3. A significant portion of people kept avoiding flying and other normal activities

• A Gallup survey in May 2021 found that, because of concern about the coronavirus, 40% of Americans said they had avoided traveling by airplane or public transportation in the previous week; 44% had avoided events with large crowds; 34% had avoided going to public places like stores or restaurants; and 26% had avoided small gatherings with family or friends. (news.gallup.com) This directly supports the idea that a significant portion of people were still refraining from normal social behaviors.
• Gallup’s June 2021 update notes that while many Americans felt their lives were “somewhat” back to normal, self‑reported social distancing and activity avoidance were still substantial, and these behaviors were explicitly linked to ongoing concern about COVID‑19. (news.gallup.com)
• TSA checkpoint data and industry reporting show that, although U.S. air travel rebounded strongly by June 2021, it had not fully recovered to 2019 levels. For example, TSA throughput in late June 2021 was frequently around 1.8–2.1 million passengers per day, compared with 2.3–2.7 million on comparable days in June 2019, with trade press noting that even the highest‑volume day in June 2021 was still “well shy” of peak 2019 traffic. (travelagentcentral.com) That gap is consistent with a sizable share of former or potential travelers still staying off planes.

4. Fear and rules as drivers

• The Gallup surveys cited above explicitly attribute people’s avoidance of crowds, travel, and public places to concern about the coronavirus, i.e., persistent fear of infection, even after vaccines became broadly available. (news.gallup.com)
• Policy-wise, the CRS review notes that as of May 21, 2021 only 14 states had ordered full‑time in‑person instruction for all or some grades; most states continued allowing or encouraging remote and hybrid options, reflecting ongoing institutional caution and rules that kept many students out of full‑time classrooms. (congress.gov)

Conclusion By mid‑2021, after vaccines were widely available and many Americans had been vaccinated, a large share of students were still not in fully open schools, and substantial portions of the public continued to avoid flying and other normal social behaviors due to COVID‑related concerns and policies. This aligns closely with Friedberg’s prediction, so the forecast is best judged as right.