Talk of "preserving" Changsin-dong often focuses on keeping the alley's appearance as it is.
Appearance and labor are different matters
Keeping the alley's look pretty and protecting the conditions that let the people working inside keep working are different matters. Leaving an old building as it is does not by itself protect the labor conditions within it.
Asking three things together
Unless residents' housing conditions, sewing workers' labor conditions, and the industry's own sustainability are asked about together, the word preservation carries only half its meaning. The most honest attitude a visitor to this neighborhood can hold is remembering that this is not scenery but a workplace where people's livelihoods are at stake.