I think the idea is great and I totally support it.
However, the example of these two families I know well makes me wonder. I am calling them 'child' for clarity, although of course they are a bit old for that label.
Just to clarify, this is nothing to do with my own DC.
Family 1
Rent a very modest flat.
The Dad is a waiter and the Mum does unskilled part-time work.
Child went to local non-selective state school.
Family 2
Own outright house they live in: semi-detatched in nice area.
Own outright a buy-to-let they rent out in nearby nice town
Dad has a PhD from highly prestigious uni, Mum has 2 MSc from Russell Group Unis
Child went to local non-selective state school.
Family 1 lives very near Family 2, but 1 is just into a London borough, while 2 is just into Surrey.
The child from Family 2 was eligible for and was given an amazing contextual offer due to the school apparently not being great, although that child was happy and successful there. The child from Family 1 was not eligible for a contextual offer.
I'm hoping that this isn't typical of how contextual offers work.