Because your telecom regulator has teeth and there's competition? When German T-Com bought Slovak Telecom monopoly they continued just like that. Forced old ISD

Because your telecom regulator has teeth and there's competition? When German T-Com bought Slovak Telecom monopoly they continued just like that. Forced old ISDN tech on everyone for high prices (probably to clear out stockpiles) and suppressed DSL for a few years, till some last mile access for competition was required by law. BTW was in Germany myself many times and it's surprising how bad coverage there's outside city centers.