Not an oxymoron
From an NPR feature on the decline of the "two" "parties":
It may sound like an oxymoron, but Arizona's unaffiliated, independent voters are organizing themselves and banding together.
Not an oxymoron at all.
Politics requires parties, just as business requires brands. The problem with American politics is not that parties as such are bad; it's just that our "two" "parties" have stopped manufacturing usable governance.
In business, a new company (or a small existing company) grows to fill the need when major brands fail. In 1958 the three big auto companies failed to provide usable cars, so Nash quickly grew to fill the need. The big three didn't start responding to the need until Nash became a meaningful threat.
Not a perfect analogy .... You CAN write in a new candidate when existing parties fail. You CAN'T build your own car when existing carmakers fail. But in practice it comes down to the same thing, because an UNORGANIZED write-in rarely works. Only a party can assemble the required components in mass-production style to get a new leader into office and maintain his support after election.