There absolutely is in the places where people want to live. That's the entire reason why the prices have gotten so expensive. If you have ten homes open up in London, and you have 30 people who want to move there - 5 bankers, 5 tech workers, 10 middle class office workers, and 10 service workers, the bankers and tech workers will get those units, thus driving up the price. Houses in the countryside have essentially no relevance to housing in London, except that people who are priced out will eventually have to flee out to them.

I do absolutely agree that housing is should not be seen as an investment vehicle, but the next question that's worth asking is why is it such an effective investment in the first place? The simple answer is that because new supply is so drastically constricted relevant to demand, the price keeps going up very reliably. If you simply flood the market with enough supply to actually meet the demand, housing immediately stops being a productive investment. Indeed, new construction in the States has actually slowed the pace of rent increases in several cities in the past year.

You can also look a a city like Tokyo, where despite massive demand, housing prices are still reasonably affordable due to them actually building enough to meet that demand and having extremely effective public transit and enough density to make that viable.

To throw another example where I could find some data, New York City, from 2010 to 2020, added 200,000 housing units. In that same time span, the population increased by 500,000. This is a very explicit example of demand outstripping supply.