You won’t need different bikes for different tracks. Basically, track bike angles have evolved as the speeds have increased and the move from shallow 333-400m tracks to steep 166-250m tracks happened.

Also, many “sweet street fixies” that are labeled as “track bikes” have a road geometry that pales in comparison to one with a modern track geometry.

The most dramatic thing I’ve seen in terms of multiple bikes is one bike for TTs (with aerobars) and one for mass start or sprints. A more relaxed (“sluggish”) geometry helps with holding a great line. Agile handling is preferred for mass start and sprinting.