It's probably a lot simpler than that. Most of the debt held by banks is probably due to be repaid in <= 30 years. If they'll still make such a loan today then

It's probably a lot simpler than that. Most of the debt held by banks is probably due to be repaid in <= 30 years. If they'll still make such a loan today then it's reasonable to infer that they don't think property values are likely to go down significantly over that time period. From their perspective, any kind of government bailout would be great, but certainly can't be counted on. This is especially true of engineering projects, where physical reality puts hard limits on what is and is not possible before even considering costs. Printing money a la quantitative easing is trivial compared to building a giant seawall or what have you.