If there is one thing technology has been doing, it has been taking things that were once only possible with a large organization, once only possible with lots of knowledge, once only possible with lots of money; and making those things do-able by one person.

Building houses fits a few of those. So it's foreseeable that eventually someone will be able to build a house with an app, for fairly low money, fairly quickly, fairly automated, but it might be many years until it's really that cheap/easy.

A potential stop gap would be like an app that told you every single step how-to build your house: buying, delivering, cutting, etc etc etc, for the millions of edge cases of construction.