You only get into those situations if you choose to follow theory, which is not necessary. There are myriad sidelines that are adequate outside of the very top

You only get into those situations if you choose to follow theory, which is not necessary. There are myriad sidelines that are adequate outside of the very top level and will give you a playable middlegame with little to no theoretical knowledge. For example: as White, you can play 1. g3, 1. b3 or a reversed Queen's Indian and get by with zero concrete knowledge. As Black it's a little more involved but 1... d6 and 2... e5 takes about thirty minutes of research and you can play anyone under 2400.