This inevitably happens as a society grows to the point where it values stability and maintenance over freedom and growth. The chaotic nature of individual liberty encourages both creation and creative destruction, which makes wealth change hands often. When government steps in to save the people from themselves, you get stasis, and it becomes increasingly harder to make your own lot in life, whether upwards or downwards.
> Upward mobility is dead
At least in the US, this still isn't nearly as true as a lot of people think it is. Sure, someone on their first job isn't going to be able to afford a house in any one of the most desirable cities in the world (let alone the country); but in vast areas of "flyover country", people make a living, buy homes with yards, and raise children.