Waited for the slave labour to arrive
Don't forget that technology offers massive leverage in construction.
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.
I find it fascinating that after all the progress of the millennia, skillfully stacking stone is still one of the most costly things men can do.
I find it fascinating that the result of this effect is that it's unlikely to be able to build a high quality brick house ever again. Most brick houses today are just wood frames with prefab brick cladding. The brick row house tenements of 1910 are now the million dollar condos of 2010.
A bit of literary trivia: This is exactly the insight that lies behind one of Ezra Pound's most famous poems, "Canto XLV":
http://emsh.calarts.edu/alumni/bkeresey/
(Note that I don't intend to suggest any deeper comparison to Pound. For him, the idea was an insidious one, leading him on a dark path that would take him from Fascist Italy to a psychiatric institution for the criminally insane in Washington, D.C.)
http://web.archive.org/web/20031121174515/http://www.new.ox....
That's a fantastic opening sentence if ever there was one.