Qatar is surely capable of building all the stadiums in time. Qatar, one of the world's most richest countries with abundant natural sources, has sufficient budget to construct required infrastructures. In addition, time is not a problem. Qatar has seven years to finish its construction. If we have a look at the case of 2010 world cup, Republic of South Africa took two to three years to build stadiums.
Although Qatar is under criticism for alleged bribery, it is not something that FIFA announced officially. President of FIFA, Sepp Blatter, said "Once again there is a sort of storm against FIFA relating to the Qatar World Cup. Sadly there"s a great deal of discrimination and racism and this hurts me. It really makes me sad, anything that smacks of discrimination and racism." Even if bribery turns out to be true, Qatar will be reelected due to is capability.