That's true but it is the case that most people in the area only have one main bus company serving them and overlap is minimal, usually limited to a few very busy corridors such as the Great North Road so when something like this happens, people don't have other options. Even a lot of nexus and DCC supported routes are covered by GNE after the most recent round of tenders (including routes like the 25 which GNE fairly recently dropped commercially because they weren't making money on them as well as the 82, 83 etc, in Washington) so people don't have those, traditionally the bread and butter of small independents, to fall back on. Washington and Gateshead are GNE territory and this map is a snapshot of what's running there, as of a few minutes ago. Extend that west a bit and it's just as empty, even though there should be over a dozen buses on that part of the map, right now. If Arriva County Durham were to strike, the map would be similarly empty in the south of Co Durham and in Darlington.
People in parts of Gateshead and South Tyneside who might have been able to manage a walk or a lift to a metro station, while this strike is on, will be out of luck, next week, when Nexus engineers are striking, resulting in no Metros.
We've also not had a prolonged bus strike like this since the 90s. The recent Stagecoach Sunderland and Stockton strikes were pretty short, compared with what we've already had and an Arriva Northumbria strike that was threatened when the Jesmond depot was closed, resulting in drivers having to move to other depots (Blyth or Ashington) was averted at the last minute.