This is partly why aristocrats still marry other aristos - the daughters need to be absorbed into another estate, because there's not another "estate sized" inheritance available for them.
"Mummy paying for a flat in London" is obviously wildly out of the norm for most people, but for an aristocrat, it's the equivalent of the son getting the whole semi-detached house and the daughters getting six months of rent on a studio.
Reminds me of a tricky situation I had to manage at work a few years back. I had a Sikh woman working for me, who was engaged and planning to give up work once she married. She had two engagement rings worth 10k each, and was having a 100k wedding with 500 guests.
There were a lot of grumbles about how tactless she was about the 10k DJ she was having etc.
But all her family worked relatively sensible, prosperous jobs, were hugely commited in the community to supporting others, and lived in large houses with a lot of extended family. And one day she'd have to fund 100k weddings for her own daughters.
They lived to such a different economic lifestyle and culture to me that I simply saw no point in being jealous. I didn't like the 10k ring, I wouldn't like a 500 person wedding, and I loathe djs no matter what the cost. Some people just don't understand the finances of huge generational wealth - including HAM!
You need both a significant whack of capital AND THEN to live within the means of that capital.