Line shared DSL had a lot of problems in the US, but it worked well overseas.

For one, AT&T got most of the orders because their retail prices were often lower (sometimes quite a bit lower) than the wholesale prices they charged to smaller ISPs. It's really hard to compete like that. Add in fun things like initially line shared services were often over dry pair (no dial tone) and telephone company lineman often used dial tone to see if a pair was in use; leading to loss of service if a pair was repurposed for another customer.

The alternative for small ISPs was somehow find a way to overbuild a 3rd network in the area, or sell out to Earthlink, or to someone who sold out to Earthlink.