Access to everything equally is not physically possible; if we pretend it is physically possible, it's not logistically possible: no ISP is going to peer with all networks at all peering points; and no regulator is going to compel an ISP to peer with all networks at all peering points.
Unbundling is easy to define, and easy to regulate, and offers a way to get competition where it's most effective. Unfortunately, it seems to be not easy to put in place. The basic idea with unbundling is that last mile delivery is cost intensive, and has high barriers to entry, etc: a market solution isn't going to work: instead require that the last mile providers offer wholesale access to get packets to a centralized point (or points) where other providers can deliver the connectivity to rest of the networks. This actually makes sense: once you're at a carrier hotel, you have a large number of options to interconnect; getting from a central last-mile provider building to a carrier hotel is managable, but getting from each home to a specific building is capital intensive.