I question your suggestion that there is actually competition with Network Solutions today.
As I see it, ICANN and NTIA have created a body of licensed resellers of NSI registry services - NSI makes a profit no matter who sells a domain name.
As for the registries that compete with one another - one must remember that ICANN has dictated much of the basic contract with customers, hence the real difference is merely of price. I personally don't consider that a very rich differentiation of product offerings.
As for the registry sharing system - from a technical point of view it is very inadequate and has many significant flaws and should be replaced as soon as possible.
But back to the original point - that of competition - we won't have real competition until we have new TLDs, many of them, operating with terms quite different than we see from today's NSI resellers. We see some of this from the country code TLDs.