I think you are overestimating just how many big companies use a thin client-like system. But I admit I might be underestimating it. Out of personal experience, I used to work for a pretty big global company and every employee got their own work laptop to use. And that was a company with 30.000+ employees worldwide. So maybe that is my bias in this, and I would think companies like that wouldn't so easily give up their digital sovereignty.