This article written by a non-expert. The cost of genome sequencing has been relatively flat in the last couple of years; and Illumina, being the monopoly, has no incentives to reduce the cost of sequencing. Also; despite what some commenters seem to think, it doesn't get to keep the data people sequence on its devices, any more than your printer company owns the content of what you print.

One would likely get sequenced many times over a lifetime - a so-called "liquid biopsy", meaning sequencing circulating DNA & tumor cells in your blood, can catch aberrant cancer-related mutations earlier and help predict cancer / catch it earlier. Once this is mature, people will likely take this test every 5 years etc.