[clairity]

> "...'the missing middle' (i.e. 20-30m high buildings)..."

the missing middle isn't just what's between two extremes, so here, it's not 20-30m (~65-100ft, or roughly 6-10 stories) as you've stated, though i'd certainly prefer cities to adopt zoning that allows much more density too (along with the mixed-zoning, public transportation and micromobility upgrades needed to support that density).

the missing middle specifically refers to 2-6 story stick-framed buildings that can be built quickly and cheaply while also providing ~4-10× the density of single-family zoning. 6-10 story buildings don't fall in this category since they usually need at least a concrete podium for the first 1-4 stories, which puts it in a different (higher-priced) construction category.

the missing middle is literally the space between single-family homes and the 6+ story buildings that require more expensive construction techniques.