Without knowing the demographics of your shul, I can only offer these possibilities:
- Hagomel is usually said following someone having an aliyah to the Torah. Thus, if someone does not get the aliyah, he may not be saying Hagomel, though, he should .. (next point)
- The aliyah is not a requirement, and it can be said by the person even after someone else's aliyah.
The above 2 make a general assumption in Orthodox shuls (which I gather is what you attend, given your description of being in the women's section) that men are receiving the aliyah, or Hagomel is made by a man in the men's section. This would explain why you aren't hearing women make the bracha, although, technically, they could from the women's section and everyone in shul could respond. Perhaps, shul minhag or protocol isn't allowing this.
Another factor could be that people who SHOULD say Hagomel perhaps don't know when it should be said. I think most realize that they should say it after returning from the hospital / surgery or major illness. But, maybe they don't know that a transatlantic flight also qualifies them to say it, according to some opinions. There are others who feel that a flight doesn't necessitate the bracha.
So, that pretty much may leave just those who are recovering from illness or were released from prison. Perhaps, you have a healthy congregation and no ex-convicts?
As one of the comments mentioned, perhaps many of these people are saying it on a weekday when you might not be in shul?
Or, the simplest reason - no one in your shul has experienced anything at all requiring them to say Hagomel.