darkwave
Not An Expert wrote:
The IOC has capped the IAAF at 1900 athletes across all events (down from over 2000 in 2016). That’s the reason for the smaller marathon fields.
Also worth noting that this isn't just limited to athletics - other sports are being told to reduce their total # of athletes as well.
In equestrian sports, countries have traditionally fielded a team of 4, with one drop score, so that only your best 3 performers counted. That's now been reduced to 3, with no drop score, for the 2020 games.