I think it's possible for believers of different religions to co-exist, but it's not possible, if those religions teach different doctrines, for them all to be true.
That would basically make truth meaningless, left to the interpretation of the practitioner as they saw fit, creating their own truth. There would be no reason for any particular religion to exist. They would serve no purpose, other than to either satisfy the desires of the members, or line the pockets of the leaders.
I don't personally believe that all paths lead to God. I do believe there is one path, and that eventually, all must tread it. They may walk for a good part of their lives on parallel paths, but at some point, they need to find the straight and narrow path that leads to eternal life.
That means finding and following God's laws, not man's interpretation of God's laws. It's not an easy thing to find, and then continue on, but it is essential for anyone who desires to receive all that our Father has for us. Otherwise, following whatever doctrine will suffice. It will just not lead to eternal life.
So, I suppose if someone doesn't care so much about what God wants them to do, but is more interested in doing what they feel is best for them, then there really isn't any reason to follow one religion.
I choose to follow one religion because I don't believe that all religions are true. Nor do I believe that it is okay to believe that they are all the same, or that they will all lead to God or heaven. There is only one way, one truth, one light, one baptism. Many may have some truths, meaning they do have some good in them, but anything that deviates from God's word is not of Him.
I believe in one religion because I have studied, pondered, prayed, received answers and put into to practice the teachings. I've seen the changes wrought in me and in my life, and in the lives of my family and friends. I not only believe it is making me a better person here, in as much as I let it, but that it is preparing me for the next life, which is much more important than just accomplishing something here.
It is up to each one of us to discover God's path, not our own. We need to know who He is, His character, His nature, and then go from there, learning what He would have us do. In doing so, we will find that while we should respect everyone in their beliefs, that there is but one way to receive salvation and exaltation, and that is through doing things His way. Not ours.
If I actually embrace a perception of pluralism and actually believe that all religion are true then it is only sensible to actually choose one religion in other to maintain your core spiritual values, morality and even belief as well in all uniqueness, that is also maintaining one important method and way in order to reach and serve God in simplicity.
I believe religion is all simplicity of belief so even if every religion is proving to be true there's no way people will suddenly choose to practise all the religion because religion is all about uniqueness and actually seeking the face of God and you cannot seek the face of God by practicing so many religion at once because you'll you'll lose your core religious values.
For example if it has been proven that any way which one takes in life will actually lead to heaven then people will only have to embrace one way that actually pleases them because it will be difficult to adhere to so many ways and actually lose prospect and lose the reason for actually embarking on a journey to heaven
I do not believe in dynamism of religion so if it is actually proven that all religion are true then the reason why I will choose a particular kind of religion must be how it appeals to me or how the general principle seems to place my faith or please my belief, there will still be a difference in perspective and the difference in responsibility and the reason why I will choose only one religion is how right, responsible and true it will appeal to my morality and perceptions