Banks obviously didn't move into this area, and perhaps they are just too closed minded, and set in their ways. that could be the same reason they are not moving into this idea you have.
I wonder though how receptive the home buyers would be--maybe they want all of the upside, so they'll save for a house of their own, and maybe even buy a smaller one to start.
But not for property purchasers, who, as you identify would not wish to share the gains they are accustomed to see as inevitable - the fact that these gains are caused by deficit-based money does not concern them, and why should it?
However, the possibility is nevertheless there for a purchaser to acquire property using this mechanism. And note that the actual finance cost may be minimised since there is no reason why investment in the capital value of the land need not be treated as "Equity" (unlike buildings, land/location does not deteriorate).
ie while a return on capital will be paid by the occupier on the whole investment, there will be no need to repay much of the capital.
However, the real opportunity using this new form of finance arises at the other end of the telescope.
Equity Release.
The "Capital Partnership" is the best form of Equity Release there is, and wipes the floor with the existing toxic alternatives of:
(a) "reversion" (when you sell part or all of your property to an investor who gambles on how long you live); or (b) a "roll-up mortgage" - where the interest rolls up - typically at 2% over base rate.
So Aunt Agatha sells (say) 10% of her £500k house to her pension fund, or someone else's, and simply pays 10% of the market rental of the property for as long as she uses the capital.
If she doesn't want to pay cash, she can pay in further equity shares instead.
Like all Equity release schemes, the equity will likely run out one day, but this structure gives : (a) Aunt Agatha the best deal there is; (b) Pension Funds a simple new REIT look-alike investment (since LLP and LLC vehicles are tax transparent or "pass through").
To see the extent of the opportunity, in the UK over £1 trillion in property is owned by over 65's free of mortgage. "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky