People try to stave off newcomers because they don't want to be replaced and made to be undesirable. This makes sense as it is part of nature to maintain and protect security, but we should be above such instinct. If there is an upcoming person, who may become a rival/threat, I suggest giving that person at least one chance to make peace and join you, rather than immediately battle for a spot. If the seat is not big enough for two, then of course, fight for the right. But if the initial peace has never been offered, then that will probably deter those who are destined to give up, but those who will attain success will be sprinting while they are behind, while they catch up, and keep sprinting until they get so far ahead that you become invisible. This doesn't have to happen, but it will be done if necessary.
Check out these successful people who paid the dues of getting rejected!
http://goo.gl/GGz9E6 It's not right for me to add mine to this list yet.