That's true that there are legitimate reasons behind the level of investment rather than simply overconfidence. However a lot of economists etc. do think house prices are overvalued, and the rate of growth is obviously unsustainable since it's been outstripping wage growth by a huge margin for 15 odd years now. Unlike government debt, individual private debt cannot increase without bound without a gut-wrenching snapback at some point.
I dunno if it will burst so much as just cool off and gradually come down though. Probably the latter. Still a bubble though.
