511 women and 260 men have qualified, the most ever (probably in large part because of improvements in shoe technology). The vast majority of these qualifiers have essentially zero chance of qualifying for the team. Obviously a woman who runs 2:44 is pretty fast, but we all know she isn't going to make the Tokyo team. Most likely she will be at about mile 23 when the third place runner crosses the finish line.
Japan's Olympic Trials, by strong contrast, included just 10 women and 30 men. The slowest female qualifier had run 2:28:32/1:07:55 and had placed tenth at the World Championships 10,000 meters in 2017. The slowest male qualifier had run 2:12:02. Every runner in these two races had a non-zero, positive chance of making the team. The races were widely watched on television in Japan, contrary to those who argue that letting in more runners increases interest among the general public.
I am an elitist when it comes to this race. I think the sole purpose of the Trials marathon should be to select the members of the U.S. Olympic team. I know a lot of sub-elite athletes enjoy aiming for and running in the race, but I don't think catering to sub-elites is what the Trials should be about. This is not the Boston Marathon. It's the Olympic Trials.
There are practical reasons for limiting the size of the field as well. With more than 500 runners in the women's race, it will likely be difficult for runners to find their water bottles. Also, it is costly to cover travel expenses of all these people.
The trials marathon isn't a fun run and it's not about making hobby joggers feel good. It is time to tighten up the standards significantly and limit fields to truly elite runners: about 2:14/1:03 for men and about 2:32/1:11 for women.