Because of subclinical issues, most people's lives will be shorter lived than need be, and during life they will face unnecessary yet substantial, increased risk of chronic disease, viral infection susceptibility etc. as a result. It's typically difficult to decipher the role of subclinical issues in premature death and increased disease-risk however. Because the contribution is over a long time period (multi-decade) and multivariate.
A major area of contribution to subclinical factors is suboptimal nutrition. For example even on an "ideal" diet, you are not likely to get enough vitamins and minerals for longevity purposes. For example zinc, selenium, magnesium, niacin - to name just a few. Present nutritional levels are not set nor tested for longevity purposes.
They are instead set for ensuring that you don't enter an immediate, acute, disease, disability or death trajectory. So called Reference Daily Intake (RDI) and Daily Reference Values (DRVs).
Other areas contributing to subclinical factors include industrial pollutants, suboptimal exposure to sunlight, toxins, pharmaceutical drugs, biologics (e.g. vaccines).
And not but not least, because by their very definition, subclinical health issues fly "under-the-radar" because of present paradigms, or technological capabilities, or both. With that as an introduction, the reader should be better armed to appreciated what Daniel Schmachtenberger said in this clip.