No. just means you should keep making new excellent content. Re-changing your tags all the time is a bad idea. It's better to rank number #4 for a tag getting 10 million searches a month, than it is to rank #1 for a tag getting 100 searches a month.
The general rule is if the video is performing well, don't touch it. If someone comes out with a better video than yours, the "simple" solution is to make a new relevant video that's up to date, better than your past video, and better than the other videos out ranking you, so you can outrank them. "New" videos are always preferred by YouTube anyway, and if it's a new GOOD video, then boom.
At the end of the day, the quality of the video is more important than how high it ranks in search anyway.