That was supposed to be how it worked in the US, at least in the late 90s/early 00s - phone (and cable too, I think?) telco network operators were legally oblig

That was supposed to be how it worked in the US, at least in the late 90s/early 00s - phone (and cable too, I think?) telco network operators were legally obligated to let other ISP companies lease their lines and deliver service to customers. There was no real enforcement though, and network operators just waged guerrilla warfare on independent ISPs - inexplicable "delays" connecting lines for customers that disappeared if the customer got impatient and signed up for the telco instead, service limitations and outages that telco customers on the same lines didn't notice, etc - until most/all of the independent ISPs went bankrupt or gave up.