There is a valid reason why people point out that Manmohan Singh is not the people-elected leader of India. Since 1991, he is a Rajya Sabha M.P. from Assam. He has won no Lok Sabha elections in his career.
We had Rajya Sabha M.P.s as Prime Ministers before Manmohan SIngh. India Gandhi and P.V. Narasimha Rao were two Rajya Sabha M.P.s who chose to run for Lok Sabha elections as soon as they were P.M. Gujaral and Deve Gowda were Rajya Sabha M.P.s but their rule did not go far.
19 ministers in the UPA government were Rajya Sabha members. In fact, most of politicians we see on TV debating each other out are Rajya Sabha people who have rarely won elections - Abhishek Singhvi, Arun Jaitley, Ravi Shanker Prasad...the list goes on. In fact there are few National level politicians who can safely win their Lok Sabha seats - even Priyanka Gandhi has to work her charm overtime to get votes for her mother.
in 2008, the Speaker of the Lok Sabha had disallowed a notice of a privilege motion against Prime Minister Manmohan Singh during heated discussions over the India-US nuclear deal because the Prime Minister was from the Rajya Sabha. Back in 2002, the National Commission to Review the Working of the Constitution had recommended that the Prime Minister of India should be a member of the Lok Sabha
The Rajya Sabha is meant for talented people from diverse backgronds to have a say in law-making. Today, it serves as back door entry for mostly untalented politicians and rich businessmen who can never hope to win elections.