I'm not sure if the samples would be sufficient for sequencing. 23andme takes saliva samples, not sure how / if they store the samples or if there would be sufficient material left to sequence.

Also it would cost maybe ~$500 / person to do whole exome sequencing, so doing this at scale is quite costly. Thats another reason you need to be targeted when recruiting populations for sequencing, it is so expensive. also RGC spent a lot of money on a high throughout, heavily automated sequencing center, so they can sequence more cost effectively than most. Even the UK Biobank genomic project is using RGC to sequence their patients