The underlying premis seems to be that Abu Dhabi has all the leverage in this situation. I don't think it is that clear since Abu Dhabi has every reason to see Dubai continue to be viable - a collapse in Dubai, besides being an embarrasment, would bring cause huge difficulties in Abu Dhabi as well. In fact, it would shake the entire Arab world (oil or not).
So, my guess would be that both sides are treading carefully because ----its in both their interests to do so.