[michaelt]

Depends on the extent to which internet access is a fungible commodity, as opposed to different ISPs having different products.

If you had a choice of 10+ ISPs you could choose between a low-low-prices ISP that sells your browsing data to marketers, has a contention ratio of 50:1, and tries to shake down Netflix for peering money; a premium ISP with a great contention ratio and good speeds for netflix and youtube; an uncensored, privacy-loving ISP; a family-friendly ISP with powerful porn-blocking options; and so on.