Primitive Christianity Revived, Again
I'd say the short answer is no, the great religions are not at war with one another, but that within any great religion are likely some practitioners who do have the perspective of fighting to the death for one religion against the others.
I remember being in Cape Town in 1999 with my wife and newborn, met there by my parents, then refugees (from the US) in Lesotho. This was the Parliament of World Religions, which took place at a polytechnical institute. Science was represented, given a whole floor to tell the story of the universe, which my daughter, new to walking, walked through.
Outside the campus, protestors registered their sense that we were bad people because from many religions that ought not be getting along like this, as the whole point was to agitate for a violence prone multiculturalism wherein the cultures can't and don't get along, never have, never will.
One might argue the folks inside the campus were of one religion, with protestors another. Then of course one has the great throng of people preoccupied with something else besides whether religions are getting along or not.
Religions compete for new recruits and followers one could say. In big cities where they're all close together, people grow up sensing they have a choice, which used to mean jumping ship or joining the circus or something, as from horizon to horizon, uniformity in religious practice is what the authorities tried to enforce.
Twas and is in port cities (such as Cape Town) and trading towns where such forms of "ethnic purity by decree" are entirely impractical, and I think therefore more from along the coastlines, than from the interiors of landmasses, that this trend towards "all getting along" gets more emphasis (not that you don't find occasional inland oases where camel trains converge from all corners).