I would get 3 of my friends together and all cosign on a 25% share in a 4 bedroom home.

If you move out, you can sell or lease your portion. If you take up more than your 25% of the space, you pay more. (For instance, 4 guys, one gets married, they're using more of the space so they now pay 40% instead of 25%, same for bringing SO's into the mix.

1 person = 1 share of the costs, but only the original signer has rights.

Original signers also have right of primacy to purchase should someone want out, they have to offer it to the other original people before trying to find a new person.

Yes, it is complicated. Yes, it is difficult. But I don't see most people earning early just out of college or just getting into their journeyman levels in the trades being able to cop out $450k plus for their starter home.