My 2 pesos...
Whatever Q has done has kept the Deep State at bay most of the time. Otherwise, that site would never be up, not if the Deep State could help it. So if it is a simplistic code anyone could crack, the Deep State wasn’t up to the job. ;)
Assume for argument's sake the DS not only IS up to it, but has and does crack the code, every time.
Now what does it do? Bwahahahah!!! Post as Q, deny Q? Say "we are the government, and you must ignore this Q character!" DS is already active masquerading as "regular posters," doing the best it can to manage public belief and sentiment.
Not to be a downer, but consider the possibility that the DS could easily crack the code all along, but did not mess with the board because there was no need to. As long as Q is fringe/cult/LARP it’s not a serious threat. Why show your hand unnecessarily?
If I were DS, I’d let things ride until it became an “emergency”. The next step I’d take would be disruption and confusion (what we’re seeing now).
Next step would be to replace everything on the board with fake Q drops. (The reason Q tells us to archive everything.)
If that stopped working, I’d go for complete shut down / blackout. (what Q has warned us about as a possibility).
I believe they found 4chan to be comprised and secured 8chan prior to moving. Any hack will look for the weakest point. They are still trying. But you are right. No way this would be allowed if the Derp State was still in control.