Lifestyle versus predisposition: scratching my head

Have you heard about the health care systems in the U.S. that have started to sequence millions of genomes in order to unearth a few predisposition genes? Millions of dollars are now poured into this endeavor. As a result, we will eventually connect the presence of some gene variants with increased risk of conditions X, Y and Z, ... and we will know that Joe Smith carries a predisposition gene for condition Z.

The fact that these are only PREDISPOSITION genes tells you that LIFESTYLE may or may not allow for conditions X, Y, and Z to be developed. Then the logical question is, why are we so complacent about our current disease-permissive lifestyle? Should not we tackle unhealthy habits with the same enthusiasm (and the same amount of funds/resources) as the ones with which we embark on massive sequencing efforts? Is it cost-effective to allow the average American to play DARE by practicing the most disease-permissive lifestyle in the history of humankind?

Under ideal circumstances, in taking care of each individual, the health care system should combine the implementation of healthy habits along with the knowledge of the predisposition genes of the individual. Platforms such as PatientsLikeMe should match sequencing data input with physical/physiological data and health markers/outcomes. Prospective analyses of such data will suggest how "tweaks" in the lifestyle can prevent the establishment of conditions to which some are predisposed.

Since we are faraway from the ideal situation, it seems that educating the Americans in healthy prevention-oriented lifestyle is more economically sound than massive sequencing of a million human genomes. What do you think?