The way price signalling works is through failure and bankruptcy. Capitalism doesn't assume that all participants are rational; rather, it assumes that some fraction of them are irrational (possibly all of them, as long as there are some people who happen to be right despite being irrational), and that those firms will go bust, and their assets will be picked up by the people who happened to be on the right track in the first place. As long as you let those failures occur, you have a functioning market.
You're exactly correct, it's a good point. We should be watching what happens now - if the failures are allowed to happen, and the pre-built assets can be had at the market clearing rate - then growth in the future should be assured.
