As a person who spent years trying to convince Muse to focus on the competitive side of their game, let me inform you—it's not going to happen.
Muse has devoted nearly all of their development efforts on a non-competitive PvE expansion, which in the meantime has crippled Skirmish mode. This de-prioritization of Skirmish has led to: lack of new content, bad client performance, unfixed bugs, lack of regular and necessary balance changes.
You talk about a "competitive queue", but this already exists: veteran matchmaking. The problem is with the game population so low right now, separating out queueing players into "buckets" just means the less popular buckets will never actually fill. Ditto for "MMR"—the game theoretically takes a hidden MMR into account, but there are not enough players to find balanced opponents, so after 30 seconds it gives up and matches you with whoever.
You say that "open lobby" events are the answer—but between Iron Fork, Munker Mondays, Chaos Skirmish, and other one-time or more sporadic events—these have not helped the competitive scene grow.
The only path I see for future growth of competitive Guns is the following:
1. Alliance is finally released, and fails to maintain a meaningful playerbase.
2. Muse Games isn't immediately dissolved.
3. Howard finds the light of our Lord Jesus Christ.
4. Muse decides to leverage the strength of their game as one of the most unique competitive experiences on the market, refocusing entirely on Skirmish development.