It doesn't - if you look at the situation in real terms, the amount of resources available to invest is about the same (probably shrinking because some are diverted to people who aren't creditworthy and consume them). So the major effect of artificially low interest rates is to add a whole heap of artificially supported highly wasteful companies to the mix.

All that changes is the market started rewarding people with access to credit instead of people who were responsible and effective. The credit people aren't particularly capable and it'd be better if they had been forced out.