Originally, wild tomatoes are not very self-compatible, requiring cross-pollination because of their long pistils that extend far out of the flower. Stamens are entirely contained in the closed corolla.
As we know from studying the history of tomatoes, they were moved and planted in other continents, losing their natural pollinators (a specific bee species), which lead to a selection of self-pollenizing varieties, which remain the most used today (actually, they are specifically selected for cultivation).
Despite several sources claiming so, tomatoes are largely not self-pollinating, since they still require external aid (either by wind, vibrators or specifically selected bumblebees).
This is necessary because of the structure of the plant: the anther is shaped as a tube, and pollen is produced inside the tube (most other species produce it on the outer surface). The only way for pollen to reach the outside is passing through small pores in the anther, but this is generally not accomplished without external vibrations.
In the wild, wind is generally enough for them to be able to self-pollinate, while in closed ambients the best option is usually represented by sonicating bees, such as the aforementioned bumblebees, or the original halictid bee of their native habitat