The UK government currently seems to be slipping from one scandal to another. It is hard to remember a more visibly powerless Prime Minister (older readers feel free to give some examples below). Since the June election when the Conservative party lost its majority in the June General Election, the government has simply stumbled along.
The Brexit negotiations have been moving at a glacial pace with minimal results or noteworthy achievements. I recently labeled them almost as a "phoney war". However, this may be one factor in Theresa May's continued survival. The role of Prime Minister is currently quite undesirable for a number of members of the Conservative party. Who wants to be the Prime Minister dragging the United Kingdom out of the European Union, with no deal agreed and the British economy facing a sustained period of economic stagnation.
There are elements of the party on the pro-Brexit (or historically on the anti-Europe faction) who would relish the afore-mentioned prospect, though they would surely describe it quite differently. Boris Johnson was a late joiner to this cause when he famously declared for Brexit days ahead of the 2016 referendum. He has come as close to any since the June election to openly challenging May with his September article in the Telegraph which lay out his vision for a post-Brexit Britain that was quite different to that of May in her January speech. However the key members rallied around May and the answer to a previous article "Can Boris Oust Theresa" seems for now to be a resounding No.
The sexual harassment scandal currently enveloping Westminster has cost the Minister for Defense, Michael Fallon, his job. There are numerous MPs implicated for inappropriate behaviour. We may see a few resign in the coming weeks as further details emerge. Fortunately for May, it doesn't seem to be enough at present to topple the government or force May to stand down.
It has been a very long time since the "Irish Problem" forced a British Prime Minister to resign. The current lack of progress in forming a new government in the Northern Ireland Assembly does not seem to be a pressing issue for the British public, based on media coverage in Britain. Theresa May knows that she relies on the ten DUP Westminster seats for her working majority. The DUP can pull down this government at a time of their choosing. It just doesn't seem likely in any potential scenario short of the post Brexit border being the Irish Sea, something the Tories have emphatically ruled out. They simply can not take the risk of a Jeremy Corbyn led Labour ascending to power given his previous dialogues with republican leaders.
I haven't even mentioned the current scandal with Priti Patel and her unofficial but definitely politically motivated trip to Israel. The fact that she hasn't been dismissed by now again shows just how impotent May currently is.
This lack of power may actually be what saves her until Brexit is concluded. The analogy that comes to mind is that of the naive, deluded Islamic Caliph or Ottoman Sultan surrounded by courtiers and advisors who all have their own agendas and seek to influence the leader for their own political gain (cough... Gavin Williamson). It's a fate worse then political death for most but maybe deep down May still believes she can turn things around. It's unlikely but sure surely something has to go right after so many recent wrongs....