Rebuild Costs and Land Prices

There is one simple statistic which enables us to kill two KLN birds with one stone.
The first is that "I paid for my home out of taxed income.".
The second is a long running argument I have had with various people about the typical rebuild cost/value of an average three-bed semi as distinct from the land value.
We know from Nationwide statistics on the ratio of house prices-to-earnings, that for the period 1953 to 2001, the ratio only went above three (never quite reaching four!) twice: for a couple of years in the early 1970s bubble and for a couple of years in the late 1980s bubble.
But throughout that period, builders were happily building 200,000 - 300,000 new homes a year in all parts of the country, it is NIMBYism and land price speculation which put paid to that, we're now down closer to 100,000.
We can argue over various up or downward adjustments, but we can safely assume that builders did it to make a profit, and that their average costs per new home were less than three times an average year's salary. And we can also assume that building techniques are little changed, it's largely manual labor. The cost of copper has gone up, but the cost of white goods has gone down so it all nets off.
The average full time male annual salary is currently £26,500 (the median is much lower than that), times that by three = £80,000 (which is what I have always said).
Going back to the first KLN, yes, people paid for the bricks and mortar out of taxed income, the same as they pay for anything out of taxed income (glossing over the fact the mortgage was subsidised via MIRAS), but most people who bought before 2001 did not actually pay a penny for the land, they got that for free.
And as Land Value Tax is only on the land element, for which any pre-2001 purchaser paid effectively nothing, it is clearly not double taxation for these people.
Agreed, people who were first time buyers after 2001 will have to pay twice for the land, that's as can't be helped, but they are all still of working age and will still pay far less tax overall if we shifted taxes from earnings and output to land values.