They will not withdraw because indirectly they are enjoying power with no responsibility and becoming use to it. I feel in India there is need two or three party system and only national level party should be allowed to contest Lok Sabha Election and the regional parties should be kept away from national politics.
Communist are worst example of state level politics , they are limited to 2-3 States and represent only few people and enjoying power with no responsibility. They should be sacked from country and should be sent to either Bangladesh to whom they support and China which is the founder of Communism