> Doing what I described in New York City is exactly how Donald Trump made an initial fortune back in the 80s.

The total value of NYC real estate is approximately $2.8T. Trump has a net worth of something like $5B. Even if all of that was invested only in NYC real estate (which it isn't), it would be less than 0.2% of the NYC real estate market, which is hardly enough to have market power.

> The business model not making sense, is due to the incorrect assumptions you make. For one, that land or buildings in cities appreciate less quickly than the stock market.

That doesn't appear to be accurate. Metro housing prices have increased by more than wages but not by more than e.g. the S&P 500.

> I'm not sure what you think the difference is in practice. There may exist some construction companies that don't engage in real estate speculation, they just aren't the big or most profitable ones.

You're just pointing out that real estate speculation has been more profitable than construction, which is exactly the problem -- we make construction too expensive, on purpose, which is what increases the profitability of speculation. That some companies do both is a poor excuse to blame the construction companies for what the speculators are doing.

> The fact that the most valuable land is owned by other construction companies who have more money because of the real estate speculation.

Nobody even owns most of the land in any major US city, much less all of it. The properties that could derive the largest increase in housing units would be to replace single family homes with multi-unit complexes and the majority of existing single-family homes are owner-occupied.