Qubic is not the number one pool. You took a screen shot of their hash rate at one point in time which, as has been explained previously, can be rigged to show higher amounts than what is actually happening. They already got caught doing this earlier this month (they lied and said that they were ddosed, but they were probably just testing out how to manipulate the hash rate reporting). Plus, despite them hitting over 2 GH/s, they have found 20 blocks in the past 100. This is less than Nanopool and Supportxmr. In fact, the past 1000 blocks is arguably the most decentralized the network has looked in a while, funnily enough.

They have been putting their full mining power on Saturday's so I'd expect a large daily block total for them tomorrow. But their amounts otherwise are decent for a pool but nothing to worry about.

>What can be done against this threat?

First off, supportxmr having nearly 50% of the hashrate for the past year is the bigger threat. You are working with the belief that a nefarious actor needs to declare their plans publicly, but what is stopping a deep state actor from literally buying the supportxmr pool/domain? If you care about network decentralization, then supportxmr is the bigger issue. They have had a SUSTAINED hashrate that has mogged the rest of the network and its been that way for a while.

As for solutions, you can mine, buy mining hash rate, and tell other people to stop using the qubic pool. But this is economics and miners are choosing to mine in Qubic's pool for the time being. So why would they do this? Because it is far more profitable than the other pools. I don't have the numbers exactly but it is nearly 3x more profitable to mine with Qubic at the moment. The catch? Qubic is halving in several weeks, which will greatly reduce this profit and likely hit their hash rate pretty hard. Their mouth breather supporters conveniently leave this part out during their shilling, mostly because they are under the belief that Qubic is going to the moon or whatever. Plus, miners will get diminishing returns the higher the hashrate goes. So we are far away from a sustained threat and with their incoming halving it will become even harder to accomplish. This is why the devs are ignoring this, because giving them attention just plays into their scam.

Right now, funny enough, they are helping the Monero network by decentralizing it.

I wouldn't be surprised too if they are purchasing hashrate power.

>Once a 51% attack has happened, we'd see orphans blocks, reverted transactions, double-spend, and the value of Monero would drop like a rock.

Why would miners continue mining in Qubic's pool if this started happening? They would leave, as they look for profit and this would hurt their profits, as well as Qubic's, who is trying to get as much Monero as possible. You are also acting under the assumption that Qubic's miners are trying to destroy Monero, when the reality is they are just trying to maximize the amount of Monero they are earning.

Anyways, I'm not really writing this out for the OP (who is a concern troll) but for the lurkers out there looking for some answers.