We've had the technology to make arbitrary shapes quickly and cheaply for decades: poured concrete.
The problems with new building tech are twofold:
First of all, for most people a house is the biggest investment they'll ever make, so they're not really keen to gamble. Oh, they'll make minor gambles - but a complete new way of building houses is a tough sell.
Second of all, building a house involves so many different costs that even a big saving in one area is only a drop in the ocean on the total project cost. If I'm building a brick-and-block house, the total cost of materials and labour might be $180,000 with brickwork comprising 10% of that. That's nothing to be sniffed at - but no matter how great and cheap your brickwork replacement is, someone taking a risk and using your new tech can't possible save more than 10%.
The problems with new building tech are twofold:
First of all, for most people a house is the biggest investment they'll ever make, so they're not really keen to gamble. Oh, they'll make minor gambles - but a complete new way of building houses is a tough sell.
Second of all, building a house involves so many different costs that even a big saving in one area is only a drop in the ocean on the total project cost. If I'm building a brick-and-block house, the total cost of materials and labour might be $180,000 with brickwork comprising 10% of that. That's nothing to be sniffed at - but no matter how great and cheap your brickwork replacement is, someone taking a risk and using your new tech can't possible save more than 10%.