Saudi Arabia has little incentive to deescalate
If you haven't already, I strongly recommend that you read Adam Baron's latest piece of Yemen-alysis for the ECFR. In it, Baron does a great job of summarizing recent developments on several fronts (both literal and figurative) of Yemen's internationalized conflict. One of the most important points he makes is that Saudi Arabia's vicious campaign of airstrikes, while drawing considerable criticism from the outside world, is "remarkably popular" within Saudi Arabia. Here's how Baron puts it:
While the Saudi offensive has seemingly failed to notch up significant success, it has proven remarkably popular domestically. Furthermore, contacts have noted a surge of popularity for Mohammed bin Salman. These factors, in addition to Hadi and other exiled officials’ unreserved support for the offensive in the hopes that its success would lead to their return to power, have ensured that the Saudis are under little to no pressure to bring an end to the conflict. In short, while it may appear from the outside that Saudi Arabia is under tremendous pressure to end the war, from an internal perspective, it is just the opposite.
There's so much more packed into this short piece that everyone should read and take to heart, so please read the whole thing. But one other paragraph in particular is worthy of special attention here. It concerns the gains al-Qaeda has made since the start of the war.
As the power vacuum has been exacerbated, Al-Qaeda in the Arabian Peninsula (AQAP) has taken advantage to dramatic effect, seizing control of Mukalla and much of the eastern province of Hadramawt. For the first time, AQAP is openly and actively embedding itself in and coordinating with Yemeni tribes; tribal contacts in Shabwa have said that even a number of staunchly anti-AQAP tribal leaders have agreed to truces with the group. This suggests that the situation in Al-Bayda, where AQAP fighters have openly fought alongside anti-Houthi fighters, risks becoming the norm in much of the rest of the country.
So, Saudi Arabia continues to escalate and is eager to find allies inside Yemen who can actually fight and win. AQAP--one of the most effective fighting forces in the country--is operating in the open, and making new friends. I have an official policy about making predictions on this blog ("don't do it"), so I'll let you map out your own worst-case scenarios from here.