Companies usually only pre-announce results if they believe there is something to gain by doing so, and the previews of 2021 full year figures by AT&T and T-Mobile USA are no exception. Yet the announcements underline significant differences over mobile strategy, as well as falling in line with a more general bounceback from the early impact of the Covid-19 pandemic during 2020, when there was a mass move towards home working. That move boosted fixed line Internet services while temporarily choking wireless growth, with the exception of FWA (fixed wireless access) in some areas. Another exception, in some regions, was 5G – for instance, in China the pandemic did little to arrest the great 5G build-out, which was approaching its…