I think its common sense to have the fewest "working royals" as needed (bearing in mind the size and extent of the duties each Royal House has to meet e.g. the Windsors also have the Commonwealth to represent at times). The interesting thing here with Joachim and Marie is that the implication, certainly from Marie, seems to be its wasn't entirely their choice. We are in a time when many royal houses are having to shift from the idea they can have countless members to needing a smaller model.
When Marie married him he was no longer the spare .... in reality she should have had no expectations of a life long nice life at the expense of the taxpayers.... that they were allowed to have that for many years was a benefit but Iím sure there was a plan in place to get Jokke skilled up to be independent... and Iím sure his father probably provided for them ... perhaps the French property?
I don't believe she had the expectation "of a life-long nice life at the expense of the taxpayers", what she had is the expectation to stay in the new country that she then started to call home, and as she was told to work for the DRF.
What they certainly didn't expect, is to be shoved into exile France, to give the main branch to shine. It was clear as soon as Marie appeared on the screen that she was the polar opposite of Mary, warm, engaging, genuine and truly engaged, and interested in her patronages. The grey men could have done that bit in a decent manner, slowly pulling them back from the limelight, and having them their jobs. The Dutch are doing it fabulously. And the same was/is going on with Bene.
But then I guess as long as the Schack's remain in DK, the contrast of Joachim and Marie would have always been in competition to the Derf's.