Why aren’t people building as many new houses as there’s clearly demand? Numerous factors: greenbelt laws, height restrictions, “Right to light”, NIMBYism, etc. I don’t believe I’ve seen either major political party advance a policy of making it easier to build new houses - or tall tower blocks (the nice kind, not the 1960s council flag blocks), I suspect because it would result in immediate uproar from the Daily Mail-reading types who can’t bear to see their house-values fall (I think Sunday Observer types would be a bit miffed too, if not about house prices then certainly the ecological impact: having lived in multiple countries in my life I noticed the “rural-rights” types that advocate preserving hedgerows and rambling access have a considerably larger influence in UK politics compared to other countries).