Large following is no indication of the efficacy of any religion. Islam and christianity both have used the sword/violence to spread their religion; not to speak of money power of late. In this material world, money power works.. If hinduism is dwindling it is because of many reasons a) a lot of hindus are lazy, complascent, lethargic and inward focussed b) a lot of hindus have become atheistical and pseudos pursuing the path of ratinoalism and materialism c) a lot of hindus have got waylaid and confused ; and selfishness and individual gratification has taken precedence over the truth
But lack of numbers is not a concern.. there was a time even earlier in history when atheists ruled and atheism, hedonism, materialism thrived.. and this is what Krishna referred to as adharma ; and when the deterioration is at its depths, then arrives a messiah to remedy all that.. and there is a long long way to go before a messiah even realises the need to come to this world and resurrect dharma
