https://www.sqlite.org/lang_altertable.html says sqlite supports ALTER TABLE x DROP COLUMN y.

This was added in 2021-03-12 (3.35.0) https://sqlite.org/changes.html#version_3_35_0

The bundled version of sqlite was updated to v3.35 in rusqlite two days later rusqlite/rusqlite#917

The bundled version of sqlite is v3.46.0 as of rusqlite 0.32.0
https://github.com/rusqlite/rusqlite#notes-on-building-rusqlite-and-libsqlite3-sys

We can obtain the version of sqlite using fns in https://github.com/rusqlite/rusqlite/blob/master/src/version.rs , and IMO butane could simply refuse to run if the sqlite version used is too low.