Given how few starships we see that would not be Kelvin-sized, I'm not sure any incarnation of Starfleet would have voluntarily downscaled at any point.
...TOS has none, apart from the hero ship; TOS movies have two designs plus the damsel-in-distress science boat; DSC shows almost exclusively Kelvin-sized ships while very much insisting that the TOS hero ship is part of the same universe, at the TOS size.
Timo Saloniemi
...TOS has none, apart from the hero ship; TOS movies have two designs plus the damsel-in-distress science boat; DSC shows almost exclusively Kelvin-sized ships while very much insisting that the TOS hero ship is part of the same universe, at the TOS size.
Timo Saloniemi