.................uh no .........................
Slightly different conditions does not mean a planet is incapable of supporting life.
Once again you ignore fact that Jupiter and Europa are prime candidates for life despite vastly different conditions than here on Earth. We know that conditions on those two worlds can probably allow some form of life to exist we just cannot get close enough to prove or disprove whether such life exists there yet.
If one considers the vast difference in the circumference in the orbits of Earth and Jupiter one realizes that a very large window exists around every star where one or more planets capable of supporting life can orbit. It is not merely a set distance from the host star which makes life possible. One also has to consider the size and relative temperature of said star combined with the size and mass of the planet in questions and it's chemistry. This therefore means many such planets can orbit the same star. The capability to support life dependent only on the chemistry of each of those planets.
In addition it is only some of the internal characteristics of Mars which makes it incapable of supporting life such as the lack of a magnetic field and an improperly balanced atmosphere. Those conditions are not exclusively rooted in the distance of Mars from the sun which means in other star systems a planet at such a distance from it's host star can support life if said conditions on and within that planet differ slightly. We already have confirmed from viewing other planets in other star systems that the the size of a planet is not conditional on it's distance from it's host star and therefore conditions can vary widely.
Any star in the 400 billion or so making up the milky way can feasibly and logically be the center of a system which includes multiple planets and planetary satellites capable of supporting life making the total possible number of such planets hundreds of billions.