Brands in UAE seem to be on SALE 24/7 - 365 days of the year. Is that their best Marketing strategy? Have they reached a point of no return?

Why not? If it supports the area's strategy of being "a place to come to shop", it can make everyone happy. Margin vs volume.

in UAE there is a lot of supply with lower demand, thus creating a less competitive market. Companies try to break even most of the team to avoid losses. 

Also, UAE is considered a wholesale market for GCC countries and MENA, so the market there try to target B2B operations too.