This is because they only care about their own benefits. In reality, they CANNOT cooperate and please do not sell UMDAP. UMDAP had already become a bad word in our neighbor community (please do more research on this). You said UMNO won't be able to stay alone to form its Govt.... This cannot be a comment/assumption, we need to see what they will do next then we know.
For Umno and even PAS. DAP is never really their enemy, is just always the bogeyman 😂 DAP true rivals are another non-Malays party, while PAS true rival are another Malay parties although PAS often call for perpaduan ummah is just a distraction because they strive to be dominant