This tries to capture Europe as a single coherent market, which it is not and by far.

It's comparing countries with vastly different socio-economical landscapes and sizes.

Is "using Cloudflare as a CDN but hosting everything at, say, Hetzner using generic systems/opensource components" the same as "having built a complete ecosystem with Amazon specific software"?

Getting out of the walled garden of AWS, GCP or Azure is notoriously difficult. Some european cloud providers made this one of their key selling point, advocating for openess and "multicloud". This had, to my knowledge, next to no effect.

Vendor lockin is real. Dependency to a vendor located outside of your generic law system is, indeed, a risk. But this article probably isn't the way to measure it (and it's a tough job to do)