It most definitely is not convenient. The establishment is plagued by weakness and committed to maintaining that culture.
While I'm arguing this, I'm also arguing against a 3rd party edgelord. It's really hard to say who is more insane, people who want to go 3rd party in a FPTP system, or people who think the Democratic establishment is competent at running elections.
Absolutely true and entirely useless on a national scale right now. FPTP is what we have and it's the system in which we must elect candidates who will move us to a better system. Primaries are where the game has to be played right now, and for that we need to kill the notion that loyal Democrats shouldn't criticize sitting Democrats.
Portland is not politically typical. It can be a model, but it has to be a model for political culture before it can be a model for how to enact a better voting system.