Over the past decade, virtualisation, softwarisation, disaggregation, and cloudification have broken apart the vertically integrated, hardware-centric model that defined European telecoms. Open source has been both engine and beneficiary of that shift, with foundations acting as de facto standards bodies and projects like OpenStack, Kubernetes, Sylva, and CAMARA becoming industry defaults. Drawing on a vision paper based on 17 interviews across operators, vendors, foundations, regulators, and EU institutions, this talk argues the binding constraint on a more sovereign telecoms industry is capability, not code. Europe leads global open source contribution yet struggles to convert that into commercial scale or strategic control in the telecoms industry. Using case studies of Orange, Deutsche Telekom, and Telenor, the talk maps engagement across operator tiers and sets out what the EU and the telecoms industry can do together to strengthen the use of open source for technical autonomy.