In order for that to happen the other 7,000,000,000 billion or so people will all have have to have died. That could create some problems. However, if you're talking about having no relatives, no wife, mother, father, brothers or sisters or cousins, or even friends in the world, then you'd be just like millions of other people who manage to live life despite their being 'alone.'
My view? I don't think it is possible to be entirely alone, no, not even if one is marooned alone on an island. It might be lonely on that island, but the fact that there are others in the world brings with it hope that the aloneness won't last forever.