The thing about demo, the negative effects were felt more in the urban areas than in the rural areas. After the first 2 months, by Jan or so, rural areas had enough money, especially the Hindi belt, including UP. So there was no real negative impact beyond Feb once enough money was in circulation.
If you're referring to the UP elections, I think one can safely say now that the negatives against the SP & the father son family drama far outweighed the severe inconveniences caused by the Demonetization. And they were severe.
Since the BSP had a shot at power too, I think the electorate there thought its time the BJP were given a chance. Maladministration and other factors may have definitely played their part in making the BJP the party of choice.
These elections were mostly to do with punishing BJP, not a pro-Congress election. Congress failed miserably in Telangana and Mizoram, so it's not like people are really interested in what RaGa has to say. The SC/ST Act was devastating. BJP ironically lost both upper caste and lower caste votes at the same time for no fault of their own.
Every election is lost by the ruling party rather than won by the opposition.
Congress has only itself to blame in Telagana. After literally burning their party in AP, they let KCR & his TRS walk away with all the credit for the creation of Telangana. Not one to look a gift horse in its mouth, KCR did his best to consolidate his position with the many people friendly schemes there courtesy which he's been re elected there.
RaGa contrary to what his die hard supporters and the satraps have to say has had a negligible impact on the elections. But as he heads the organization, he is entitled to his share of bouquets just as when the organization slips he'd get his share of brickbats too.
In the final analysis, Modi was primarily elected to right the economy . He attempted to do that but having failed quickly moved to ameliorate the situation by better governance with fringe benefits like DBT's, Gas connections, girls education, swacch Bharat, etc.
Issues like rural distress, agricultural woes have been there and will continue to bedevil which ever administration is in power in India. Industrialisation of the economy is an imperative. That's what Modi promised and failed to deliver in spite of his best efforts. That more than anything else mattered in the end.