It is very evident that umpires are still biased against Bangladesh. Whenever there is a benefit of doubt, the benefit favours the more established side. Umpiring mistakes against established sides like Australia are taken very seriously but brushed aside when it is against Bangladesh. The DRS is a very effective system and can easily find umpiring mistakes. It is very expensive though. In Australia, when DRS system is used, you can always see the name of a company written at the corner of the screen which sponsors the DRS system. I'm sure there are many companies in Bangladesh willing to sponsor the DRS system. People criticise Bangladesh team for their poor performance, but no one ever talks about the poor umpiring.