The argument that inclusionary zoning is a major barrier to housing construction is short-sighted. Regardless of if the new housing is built in the existing zoning district or on the property, we would expect it to take longer and result in a smaller fraction of units being built if the new units were built with inclusionary zoning.
Even if an apartment building is not required to include units that would otherwise be included by zoning, and even if zoning keeps units below market rate for 20 years, constructing a new apartment building that is not required to include affordable units is unlikely to result in less housing being built. In the absence of inclusionary zoning, housing production would be driven by the weakest demand and its highest allocation of land value. Land value in the lowest tier of the market is, and will continue to be, more sustainable than demand for high-end housing. This is where the significant needs of low-income people are addressed by affordable housing and where the highest value housing is created.