The United States will not be more competitive in the next olympics when it comes to the women's 10k. Historically, East African athletes dominate long distance running events at the olympics. Additionally, the United States seems to put more focus onto other events such as swimming and gymnastics. As long as the United States continues to invest time and money into the more high-profile olympic events, East Africa will remain the most successful competitor in the women's 10k.
No, the U.S. will not be more dominant in the women's 10k next Olympics. While it's difficult to say for certain what may happen four years from now, the U.S. has tended to excel in other sports. Women's fencing, swimming, and gymnastics are where the U.S. is most competitive, and coaches and athletes will want to keep up that reputation as champions in those sports.
There is only one female United States Olympian who has recently medaled in the women's 10k, and that is Shalane Flanagan. She might compete in Tokyo in 2020, but she only received a bronze in Beijing. Before Beijing, a woman from the United States won another bronze in 1992. Otherwise, the event has been dominated by East African runners. If past trends are any indication, East African runners will still dominate the women's 10k in Tokyo 2020.
Track and field has never been a popular sport in the United States. Because of this we do not send many track and field athletes to the Olympics, which allows other countries, such as East Africa to dominate in the events. This is not likely to change in the future.