GIMP had the migration to GTK 3.0 (which is already outdated and replaced by 4.0) recently. It modernised a lot of things but didn’t change the UX fundamentally.
The FOSS space is unfortunately greatly lacking in skilled UX designers, and major reworks to long standing existing projects are always a gigantic undertaking that require a coordinated effort that can’t just be banged out by one very motivated dev, so it rarely happens.
GIMP had the migration to GTK 3.0 (which is already outdated and replaced by 4.0) recently. It modernised a lot of things but didn’t change the UX fundamentally.
The FOSS space is unfortunately greatly lacking in skilled UX designers, and major reworks to long standing existing projects are always a gigantic undertaking that require a coordinated effort that can’t just be banged out by one very motivated dev, so it rarely happens.