Such a model wouldn't work because the backend and frontend of a site are far much more work than a logo.
That isn't to say you couldn't spend an equivalent amount of man-hours designing a logo. But it is to say that the designs on 99designs obviously don't have the same amount of work put into them, otherwise the site would be infeasible.
You can argue otherwise, but the fact that there isn't a business for this just like 99designs flourishing is enough proof for me that it won't work.
Also, if someone wants to make such a business, I welcome it. Doesn't mean I'll participate.
That isn't to say you couldn't spend an equivalent amount of man-hours designing a logo. But it is to say that the designs on 99designs obviously don't have the same amount of work put into them, otherwise the site would be infeasible.
You can argue otherwise, but the fact that there isn't a business for this just like 99designs flourishing is enough proof for me that it won't work.
Also, if someone wants to make such a business, I welcome it. Doesn't mean I'll participate.