But is used by the writer either to emphasize, or to compel the reader to perceive, comparatively that a subsequent situation is happening despite of the initial situation.
Even if you the reader do not wish to perceive it that way, the writer being the writer has the volition to portray it that way. The writer wants to conjure in you a differential or unlikely relationship between the basis and the consequence, even if you, the reader, may not agree there is a differential relationship.
Therefore the writer is as though saying,
Despite being highly paid, all her busy schedules and having left her birth country for good, she is still concerned about the situation back there.
Examples of usage:
There is nothing but dust on this planet.
The research ship captain said to Capt Janeway, "I am but a lowly minion in the Romulan empire."
You could write:
I can have the cake and eat it too.
However, if you wrote the following instead, you are defiantly declaring that the idiom, of having the cake but not being allowed to eat it, does not apply to you.
I can have the cake but eat it too.
Oh Carol, by Neil Sedaka.
Oh! Carol, I am but a fool
Darling, I love you though you treat me cruel
Perhaps, the singer is admitting to Carol, that despite his normal existence, he had been a fool.
In more artsy speak, but is used in place of than (parallel comparison) and then (sequential events)
He is nothing more than a fool.
He is nothing more but a fool.
The sooner we reach our destination but the better we feel.
In conjunction with a subjunctive situation:
I would rather believe but that his love for me were true.
The world would stand idly by in gentle faith but that the sufferings in Syria could be solved thro peaceful negotiation.
- On the contrary: the plan caused not prosperity but ruin.
- Contrary to expectation; yet: She organized her work but accomplished very little. He is tired but happy.
- Usage Problem Used to indicate an exception: No one but she saw the prowler.
- With the exception that; except that. Often used with that: would have joined the band but he couldn't spare the time; would have resisted but that they lacked courage.
- Informal Without the result that: It never rains but it pours.
- Informal That. Often used after a negative: There is no doubt but right will prevail.
- That . . . not. Used after a negative or question: There never is a tax law presented but someone will oppose it.
- If not; unless: "Ten to one but the police have got them" (Charlotte M. Yonge).
- Informal Than: They had no sooner arrived but they turned around and left.