As a layman, it feels like studies which are not specific to individual genomes (and expressions of those genomes), and don't usually consider differences in ar

As a layman, it feels like studies which are not specific to individual genomes (and expressions of those genomes), and don't usually consider differences in areas we seem to be learning more about every hour (e.g. gut biome), are going to be antiquated as we continue to learn more in those types of areas. Said the other way, getting to the individual level will have a massive impact on how we approach health and medicine. Am I too optimistic? If and when we can get to this individual level, are we each still a very complex system with too many unknown unknowns - too many interdependencies and unknown relationships between cause and effect (even when they do exist)?