Currently you can either save and buy a house or you can rent. With rent often being the less preferred and more unappealing option as you get nothing in the end.

Why is it either or? Is there no middle ground?

Suppose three of four tenants take out a joint mortgage on a home instead or entering a rental contract with a landlord.

They can leave whenever they want (as renters can) as long as they find someone to take over their share of the mortgage payment - which is likely less costly than renting).
After 15-20 years there could be 15-20 or more participants in the mortgage payment.

When it is fully paid off the house is auctioned off (hopefully for a profit). The money is then split in proportion to contributions from each of the participants over the entire mortgage payment.

If the house appreciates enough you could end up with a pay day down the line that amounts to more than you even paid in rent to live there. And at worst you likely end up with nothing but still paid less in a mortgage than you did to rent for the same length of time.