It also helps if you can wait until a period of enormous wealth inequality so that skilled labor is basically free.

Wait?

Thats what Dubai and Abu Dhabi did.

Waited for the slave labour to arrive

I don't have data, but I suspect that labor costs these days are lower than they were back then due to a greater use of machinery. e.g., a foundation trench that would have taken a dozen men a week to dig with pickaxes, shovels and wheelbarrows can be done with one guy and a BobCat in a day.

Don't forget that technology offers massive leverage in construction.

Give it a year or so, if the Govt and Fed can't stave off deflation anymore, will be perfect timing then.

If you're talking about centuries old buildings, wealth back then was usually accumulated by way of your family passing along wealth, your inclusion in the favored aristocratic class of the era, or through businesses built on slavery.

I think they mostly depended on:

1) extremely cheap to free labor.

2) community effort. Everybody contributed to important buildings. Private homes would be built by the entire family, and possibly neighbors too.

Or they announced a special sale on indulgences.

Doesn't Groupon sell those now?

I saw some online during a Woot-off, between LED toenail clippers and the 'bag of crap'.

That was either one of the more hilarious comments I've read on HN, or I'm too drunk to know any better. Either way, have an upboat.