At some point they may have to pivot to multi-family;though, don’t you think? With farmland values being what they are, the answer can’t automatically be just keep expanding the metro and buy more farmland. Certainly that will still be happening, but perhaps at a slower pace (and not necessarily for first time homebuyers)?
Farmland price has very little impact on housing costs. Developers can and do pay far above farm value, and development costs (developers pay for the new streets, water mains, sewers, and a multitude of fees and off-site costs) along with soft costs like financing, are vastly greater percentages of overall costs than are the land costs.
"Green field" development is almost always cheaper than "brown field" development, ie redevelopment in an existing neighborhood, where there are demolition costs, possibly environmental conditions, and infrastructure issues. Plus existing homes will be valued less than new construction, which has a negative effect on appraisals for the new construction and affects feasibility.
UNLESS an existing residence can be "flipped" in a high value market, commonly in higher amenity metro locations where there aren't any green fields, OR density can be increased to offset the higher cost of the brown field location, OR there are public subsidies to reduce the redevelopment expenses.