Re: The problem is not Linux itself...
> Presumably also, "field workers and teleworkers" are absolutely not using unauthorised business-specific apps on their computers. So we are talking about standard office functionality, aren't we?
No, we're not necessarily talking about standard office functionality.
Consider a roads inspector out and about inspecting repairs or reporting on repairs required. Ideally he'll have a tablet (or at least a laptop) with access to mapping software showing underground utilities - pipes, power cables etc. so that he can cost-up the impact the proximity of utility infrastructure will have on the job there and then rather than later, back at the office, when there is no chance to go back and have a second look.
Historically that kind of software was Windows only - whether on a laptop or back in the office. Ironically for Lower Saxony, the ready availability of powerful tablets means that type of capability is now becoming tablet only, i.e. iOS and Android!