I think the difference with the first 5 is that a manufacturer sets the price, scalpers purchase it by that price and sells it at a much higher one.

The house price just fluctuates continuously and when the “investor” or “scalper” purchases it, it was available at that price for everyone (or did he purchase it from another scalper?)

Yes, the problem is the high prices of houses, but to reduce it we need to either increase supply (encourage building more, perhaps changing zoning laws to allow more homes etc) or reduce demand (increase interest rates (that though make it harder for regular people), restricting corporations from purchases, banning Airbnb (yes, they drive prices up, and if you use them, you are contributing to it), penalizing if unit is not occupied (though enforcement of this will be hard), or banning foreign investors.

Buying up enough of something so that you’re one of the only names in town is a “smart business move”, because then you can start to charge whatever prices you want. Totally not scalping. You see it in private healthcare, food, newsmedia, streaming, telecom.