If they knew, why then did they need to adjust their fees after initial announcement? Looks like the management is pretty disconnected and desperate to me.
Cannot speak for everyone, but the builds of my team are heavily parallelized, and we aren't even running a monorepo. For any non-trivial project that has its own somewhat complex build pipeline with many internal dependencies and such, it is pretty much a given.
The only scenario I can foresee where people wouldn't be doing parallel builds is if they are just working on their personal side project with no other people involved, where the need for parallel builds is non-existent either way. You don't want to have one giant monolith project for your whole complex web app, it becomes a nightmare very quickly.
I'm pretty sure they blew through most of their estimates.
The projects was always hailed as one of the big crowdfunding break and nothing indicates they considered borrowing to finance the project given the massive amount of money they got and the time estimates they posted.
It would be irresponsible to operate entirely off of crowdfunded cash because that money could go a lot farther if properly invested. If you invest, then sometimes you need more cash that you have on hand. You could sell some of your assets, but if you can reliably anticipate they'd sell for significantly more at some future time (relative to interest rates), then you're better off taking a loan and then paying it off when you sell assets later.
Apple takes out loans in the US because their offshore billions are subject to 30ish % corporate tax if repatriated, which is indeed a tax incentive albeit a perverse tax dodging one...