Economics is a zero sum game

>Each dollar spent has more economic impact than just a dollar.
nope, a dollar spent means it is not able to be invested in the future to get a bigger return, spending a dollar instead of investing it leads to decivilization

And if you didn't spend that $1 million, it would be loaned out or in the markets, doing the exact same thing.

take an econ class

>In addition, my money hasn't vanished; most of it has been distributed among the architect, the builders, the foreman, and anyone else who helped build the house

This is disingenuous keynesianism. The wealth generating function is, as you state, the building of the house. There is now a house there that was not there before and its owner is wealthier for it. How much wealthier that makes its owner depends on the variable amount that he (and other potential owners of the property) value the house as opposed to a haphazard pile of unworked construction materials.

But to get the house the land owner has to make a trade with the house builder, who trades his time, sweat, and expertise. Because the land owner is not a house builder he values the other person's time, sweat, and expertise more than that person does and so he will trade something (it can be anything, but in modern times we tend to use money) that's less than what he values the house at, but more than what the builder values his own time, sweat, and expertise at. In this way, they both "profit". The quantities of wealth can't be expressed in currency, but rather the difference between the currency lost or gained and what each individual person would be willing to accept to be party to the transaction.

Extremely Dumbed Down Example: Person A asks Person B to do a job for $10. A values the results of that job at $12, B values his time and effort at $9. The equivalent of $3 of "real wealth" are generated out of thin air.

It's only zero-sum in the short run.

Anything past that and its still very well approximated by a zero-sum model however.